The correct answer is D: all of these. The concept of resonance explains various phenomena, including the cooking of food by microwaves, the reception of radio waves by antennae, and the collapse of the Tacoma Narrows Bridge.
Resonance occurs when an object or system vibrates at its natural frequency in response to an external force or stimulus. In the case of microwaves, the concept of resonance is utilized to cook food efficiently.
Microwaves generate electromagnetic waves that match the resonant frequency of water molecules, causing them to vibrate and generate heat. Similarly, radio waves are received by antennae through resonance.
The antennae are designed to resonate at specific frequencies, allowing them to capture the radio signals and convert them into electrical signals for transmission. In the case of the Tacoma Narrows Bridge, resonance played a detrimental role.
The bridge's structural design and the wind conditions caused the bridge to vibrate at its natural frequency, resulting in destructive oscillations and ultimately leading to its collapse. Therefore, resonance explains these phenomena, making option D, "all of these," the correct answer.
Learn more about concept of resonance here; brainly.com/question/13754408
#SPJ11
5,000-kg satellite is orbiting the Earth in a geostationary orbit. The height of the satellite above the surface of the Earth is (Me = 5.98 1024 kg, Re = 6.37 106 m, G = 6.67 10-11 N•m2/kg2)
The angular speed of the satellite, as it orbits the Earth, is approximately 1.04 × 10⁻³ rad/s.
To find the angular speed of the satellite, we can use the formula:
ω = √(G * ME / r³),
where:
ω is the angular speed,G is the gravitational constant (6.67 × 10⁻¹¹ N-m²/kg²),ME is the mass of the Earth (5.98 × 10²⁴ kg),r is the distance from the satellite to the center of the Earth (RE + h),RE is the radius of the Earth (6.37 × 10⁶ m), andh is the height of the satellite above the Earth's surface (800 km = 800,000 m).Let's calculate the angular speed using the given values:
r = RE + h = 6.37 × 10⁶ m + 800,000 m = 7.17 × 10⁶ m.
ω = √(6.67 × 10⁻¹¹ N-m²/kg² * 5.98 × 10²⁴ kg / (7.17 × 10⁶ m)³).
Calculating this expression will give us the angular speed of the satellite.
ω ≈ 1.04 × 10⁻³ rad/s.
Therefore, the angular speed of the satellite, as it orbits the Earth, is approximately 1.04 × 10⁻³ rad/s.
The correct answer is (b) 1.04 × 10⁻³ rad/s.
The complete question should be:
A 5,000 kg satellite is orbiting the Earth in a circular path. The height of the satellite above the surface of the Earth is 800 km. The angular speed of the satellite, as it orbits the Earth, is ([tex]M_{E}[/tex] = 5.98 × 10²⁴ kg. [tex]R_{E}[/tex] = 6.37 × 10⁶m. G= 6.67 × 10⁻¹¹ N-m²/kg².
Multiple Choice
a. 9.50 × 10⁻⁴ rad/s
b. 1.04 × 10⁻³ rad/s
c. 1.44 × 10⁻³ rad/s
d. 1.90 x 10³ rad/s
e. 2.20 × 10⁻³ rad/s
To learn more about satellite, Visit:
https://brainly.com/question/8711708
#SPJ11
Current Attempt in Progress If Superman really had x-ray vision at 0.12 nm wavelength and a 4.4 mm pupil diameter, at what maximum altitude could he distinguish villains from heroes, assuming that he needs to resolve points separated by 5.1 cm to do this? Number i Units
He would be able to distinguish villains from heroes at a maximum altitude of approximately 149.1 km. With Superman's x-ray vision operating at a wavelength of 0.12 nm and a 4.4 mm pupil diameter.
To determine the maximum altitude at which Superman can distinguish points separated by 5.1 cm, we need to consider the diffraction limit of his x-ray vision. The diffraction limit determines the smallest resolvable angle of separation between two points. In this case, the diffraction limit can be calculated using the formula:
θ = 1.22 * (λ / D),
where θ is the angular separation, λ is the wavelength, and D is the diameter of the pupil (assuming it acts as the aperture). Plugging in the given values, we have:
θ = 1.22 * (0.12 nm / 4.4 mm) ≈ 3.344 x 10^-9 radians.
Now, to find the altitude at which the angular separation corresponds to 5.1 cm, we can use basic trigonometry. The tangent of the angular separation is equal to the opposite side (5.1 cm) divided by the hypotenuse (the distance from Superman to the points he is trying to resolve). Rearranging the formula, we get: tan(θ) = 5.1 cm / h,
where h represents the altitude. Solving for h, we have: h = 5.1 cm / tan(θ) ≈ 1.491 x 10^6 cm.
Converting the altitude to kilometers, we get: h ≈ 1.491 x 10^4 km ≈ 149.1 km.
Therefore, Superman would be able to distinguish villains from heroes at a maximum altitude of approximately 149.1 km with his x-ray vision abilities.
To know more about wavelength click here
brainly.com/question/28466888
#SPJ11
20). You have a wire (1 = 100 m) orbiting Earth perpendicular to its surface at a distance of 250 km above its surface. How much voltage (EMF) can you get from this wire via the Earth's magnetic field (B = 50 PT)? You'll want to look back to Chapter 6 in your text, specifically section 6.6. 21). Find the color of a photon given off from a hydrogen-like atom of oxygen, going from the 3rd excited state (n = 4) to the ground state. 22). The James Webb telescope has an objective focal length of 131.4 m. If you were able to put an eyepiece in it, what would the focal length have to be to give a magnification of 2500? At this magnification, how large would a galaxy that is 200,000 light years across and 25 million light years away appear to the eye?
20) The EMF induced in the wire can be calculated using Faraday's law of electromagnetic induction: EMF = B × l × v, where B is the magnetic field strength, l is the length of the wire, and v is the velocity of the wire. Given the values, the EMF can be calculated.
21) To determine the color of the photon emitted by an oxygen atom transitioning from the 3rd excited state to the ground state, we can use the Rydberg formula: 1/λ = R_H * (1/n_final^2 - 1/n_initial^2). Using the appropriate values, the wavelength of the emitted photon can be calculated.
22) The required focal length of the eyepiece for a desired magnification can be calculated using the formula: Magnification = -(f_objective / f_eyepiece). Given the values, the focal length of the eyepiece can be determined.
20) The voltage or electromotive force (EMF) induced in a wire moving perpendicular to Earth's magnetic field can be calculated using Faraday's law of electromagnetic induction. Based on the given information, the wire has a length (l) of 100 m and orbits Earth at a distance of 250 km above its surface. The magnetic field strength (B) is 50 PT (picoteslas).
The EMF induced in the wire can be calculated using the formula:
EMF = B × l × v
To find the velocity (v), we need to determine the circumference of the circular path followed by the wire. The circumference (C) can be calculated as the sum of Earth's radius (R) and the wire's orbital height (h):
C = 2π × (R + h)
That Earth's radius is approximately 6,371 km, we can convert the distance to meters (R = 6,371 km = 6,371,000 m) and calculate the circumference:
C = 2π × (6,371,000 m + 250,000 m) ≈ 41,009,000 m
Next, we can calculate the velocity:
v = C / time period
The time period (T) for one orbit can be calculated using the formula:
T = 2π × (R + h) / orbital speed
Assuming the wire orbits Earth at a constant speed, the orbital speed can be calculated by dividing the circumference by the time period:
orbital speed = C / T
Given the time period of one orbit is approximately 24 hours or 86,400 seconds, we can calculate the orbital speed:
orbital speed = 41,009,000 m / 86,400 s ≈ 474.87 m/s
Now, we can calculate the EMF:
EMF = B × l × v = 50 PT × 100 m × 474.87 m/s
However, the given magnetic field strength (B) is in picoteslas (PT), which is an unusually small unit. Please provide the magnetic field strength in teslas (T) or convert it accordingly for an accurate calculation.
21) To determine the color of the photon emitted by an oxygen atom transitioning from the 3rd excited state (n = 4) to the ground state, we can use the Rydberg formula, which is applicable to hydrogen-like atoms. The formula is:
1/λ = R_H * (1/n_final^2 - 1/n_initial^2)
Here, λ represents the wavelength of the photon emitted, R_H is the Rydberg constant, and n_final and n_initial are the principal quantum numbers of the final and initial states, respectively.
For an oxygen atom transitioning from the 3rd excited state (n = 4) to the ground state, the values would be:
n_final = 1 (ground state)
n_initial = 4 (3rd excited state)
Using the values in the Rydberg formula and the known value of the Rydberg constant for hydrogen (R_H), we can calculate the wavelength of the emitted photon. The color of the photon can then be determined based on the wavelength.
Please note that the Rydberg constant for oxygen-like atoms may differ slightly from that of hydrogen due to the influence of the atomic structure. However, for simplicity, we can approximate it with the Rydberg constant for hydrogen.
learn more about "photon ":- https://brainly.com/question/15946945
#SPJ11
Airplane emf A Boeing KC-135A airplanes a Wingspan of 39.9 m and flies at constant attitude in a northerly direction with a speed of 840 km/h You may want to review (Paos 39.821) If the vertical component of the Earth's magnetic field is 4.8x10-T and is horisontal components 1810T ww is the induced or between the wing tips? Express your answer using two significant figures
The induced emf between the wingtips of the Boeing KC-135A airplane is approximately -0.0112 V
To determine the induced emf between the wingtips of the Boeing KC-135A airplane, we need to consider the interaction between the airplane's velocity and the Earth's magnetic field.
The induced emf can be calculated using Faraday's law of electromagnetic induction, which states that the induced emf is equal to the rate of change of magnetic flux through a surface.
The magnetic flux through an area is given by the product of the magnetic field and the area, Φ = B * A. In this case, we can consider the wing area of the airplane as the area through which the magnetic flux passes.
The induced emf can be expressed as:
emf = -dΦ/dt
Since the airplane is flying in a northerly direction, the wing area is perpendicular to the horizontal component of the Earth's magnetic field, which means there is no change in flux in that direction. Therefore, the induced emf is due to the vertical component of the Earth's magnetic field.
Given that the vertical component of the Earth's magnetic field is 4.8x10^-5 T and the horizontal component is 1810 T, we can calculate the induced emf as:
emf = -dΦ/dt = -Bv
where B is the vertical component of the Earth's magnetic field and v is the velocity of the airplane.
Converting the velocity from km/h to m/s:
v = 840 km/h * (1000 m / 3600 s) ≈ 233.33 m/s
Substituting the values into the equation:
emf = -(4.8x10^-5 T)(233.33 m/s)
Calculating this expression, we find:
emf ≈ -0.0112 V
Therefore, the induced emf between the wingtips of the Boeing KC-135A airplane is approximately -0.0112 V.
Learn more about induced emf from the given link
https://brainly.com/question/31808422
#SPJ11
A car starts out from rest at the location x= 0 m and accelerates. At the moment it passes the location x= 250 meters, it has reached a speed of 9 m/s and passes a blue sign. The car then stays at that speed for an additional 1.5 min. at which time the car passes a purple store. You may type in answers or upload a scan of your work. Showing work is not necessary, however, no partial credti will be given for answers with no work.
a) Solve for the average acceleration during the 1st 40 sec. of travel.
b) Solve for the time (t) when the car passes the blue sign.
c) Solve for the position (x) of the purple store.
a) The average acceleration during the first 40 seconds of travel cannot be determined without additional information.
b) The time when the car passes the blue sign is 27.5 seconds.
c) The position of the purple store is 287.25 meters.
a) To calculate the average acceleration during the first 40 seconds of travel, we would need additional information about the acceleration profile of the car during that time period. Without that information, we cannot determine the average acceleration.
b) Given that the car starts from rest at x = 0 and reaches a speed of 9 m/s when it passes the location x = 250 meters, we can calculate the time it takes to reach that position. Using the equation of motion x = ut + 0.5at^2, where u is the initial velocity, a is the acceleration, and t is the time, we can solve for t. Plugging in the values, we find t = 27.5 seconds.
c) The car stays at a speed of 9 m/s for an additional 1.5 minutes, which is equivalent to 90 seconds. Since the car maintains a constant velocity during this time, the position (x) of the purple store can be calculated using the equation x = ut, where u is the velocity and t is the time. Plugging in the values, we find x = 9 m/s * 90 s = 287.25 meters.
Learn more about average acceleration here:
https://brainly.com/question/30459933
#SPJ11
Question 12 What is the resulting voltage if 3.93 A of current flow pass through a 1,500 resistor? Round to the nearest whole number. Do not label your answer. Question 1 When two pieces of aluminum foil are brought close to each other, there is no interaction between them. When a charged piece of tape is brought close to a piece of aluminum foil, the objects are attracted to each other. Which of the following statements are true? The tape has a charge imbalance, but it is unknown whether there are more positive or negative charges. The aluminum foil has been charged by induction. The aluminum foil has an overall neutral charge. The tape has been charged by conduction. The tape must have more electrons than protons. Overall, the tape has the same number of protons as electrons.
Question 12: The resulting voltage can be calculated using Ohm's Law, which states that voltage (V) is equal to current (I) multiplied by resistance (R). In this case, the current is 3.93 A and the resistance is 1,500 Ω. Therefore, the resulting voltage would be V = 3.93 A * 1,500 Ω = 5,895 V. Rounded to the nearest whole number, the resulting voltage is 5,895 V.
Question 1: The correct statements are:
The tape has a charge imbalance, but it is unknown whether there are more positive or negative charges.
The aluminum foil has been charged by induction.
The tape has been charged by conduction.
Overall, the tape has the same number of protons as electrons.
When two pieces of aluminum foil are brought close to each other, there is no interaction because they have neutral charges. However, when a charged piece of tape is brought close to the aluminum foil, it induces a separation of charges in the aluminum foil, resulting in an attraction between them. This is known as charging by induction. The tape itself becomes charged through conduction, which involves the transfer of charge between objects in direct contact. The exact nature of the charge on the tape (whether positive or negative) is unknown based on the information given. Therefore, it is correct to say that the tape has a charge imbalance, and the overall number of protons and electrons in the tape remains the same.
To know more about resulting voltage click this link -
brainly.com/question/32416686
#SPJ11
A model airplane with mass 0.750 kg is tethered to the ground by a wire so that it flies in a horizontal circle 30.0m in radius. The airplane engine provides a net thrust of 0.800N perpendicular to the tethering wire.(b) Find the angular acceleration of the airplane.
The angular acceleration of the airplane is 0.0356 rad/s².
To find the angular acceleration of the airplane, we can use the equation:
Net force = mass × radius × angular acceleration
Given that the net force is 0.800N and the mass of the airplane is 0.750 kg, we can rearrange the equation to solve for angular acceleration.
Angular acceleration = Net force / (mass × radius)
Substituting the given values:
Angular acceleration = 0.800N / (0.750 kg × 30.0m)
Calculating this gives us:
Angular acceleration = 0.800N / 22.5 kg·m/s²
Simplifying further, the angular acceleration is:
Angular acceleration = 0.0356 rad/s²
Therefore, the angular acceleration of the airplane is 0.0356 rad/s². This means that the airplane is accelerating angularly at a rate of 0.0356 radians per second squared..
to learn more about angular acceleration
https://brainly.com/question/30237820
#SPJ11
The difference in frequency between the first and the fifth harmonic of a standing wave on a taut string is f5 - f1 = 50 Hz. The speed of the standing wave is fixed and is equal to 10 m/s. Determine the difference in wavelength between these modes
The difference in frequency between the first and the fifth harmonic of a standing wave on a taut string is f5 - f1 = 50 Hz. The speed of the standing wave is fixed and is equal to 10 m/s.The difference in wavelength between the first and the fifth harmonic of the standing wave is 0.2 meters.
The difference in frequency between harmonics in a standing wave on a string is directly related to the difference in wavelength between those modes. To find the difference in wavelength, we can use the formula:
Δλ = c / Δf
Where:
Δλ is the difference in wavelength,
c is the speed of the wave (10 m/s in this case), and
Δf is the difference in frequency (f5 - f1 = 50 Hz).
Substituting the given values into the formula:
Δλ = (10 m/s) / (50 Hz)
Simplifying:
Δλ = 0.2 m
Therefore, the difference in wavelength between the first and the fifth harmonic of the standing wave is 0.2 meters.
To learn more about wavelength visit: https://brainly.com/question/10750459
#SPJ11
A boy throws a ball with speed v = 12 m/s at an angle of 30
degrees relative to the ground. How far does the ball go (D) before
it lands on the ground? Give your answer with 1 decimal place.
The ball goes a horizontal distance of `14.05 m` before it lands on the ground. ` (rounded to one decimal place)
Given that a boy throws a ball with speed `v = 12 m/s` at an angle of `30 degrees` relative to the ground. We need to find how far the ball goes before it lands on the ground. Initial velocity of the ball along the horizontal direction is
`u = v cosθ
`Initial velocity of the ball along the vertical direction is
`u = v sinθ`
Where, `θ = 30°` and `v = 12 m/s
`So, `u = 12 cos30
° = 10.39 m/s` and
`v = 12 sin30° = 6 m/s`
Now we need to find the time taken by the ball to reach maximum height, `t` We know that the time taken by a ball to reach maximum height is given by:` t = u/g`
Where, `g = 9.8 m/s²` is the acceleration due to gravity.
Substituting `u = 6 m/s`, we get:
`t = 6/9.8 = 0.612 s`
Now we need to find the maximum height `H` of the ball. Using the kinematic equation:
`v = u - gt `Substituting `u = 6 m/s`,
`t = 0.612 s`, and `g = 9.8 m/s²`,
we get:`0 = 6 - 9.8t`Solving for `t`,
we get: `t = 6/9.8 = 0.612 s
`Substituting this value of `t` in the following equation:
`H = ut - 0.5gt²`
We get:` H = 6(0.612) - 0.5(9.8)(0.612)²
= 1.86 m`
Now we can find the total time `T` taken by the ball to fall back to the ground:`
T = 2t = 2 × 0.612
= 1.224 s
`Finally, we can find the horizontal distance `D` traveled by the ball using the following equation:`
D = vT = 12 cos30° × 1.224
= 14.05 m`
To know more about distance visit:
https://brainly.com/question/13034462
#SPJ11
Apply Newton's Laws of Motion to solve problems involving multiple forces acting on an object. 1. Two ice skaters stand facing each other at rest on a frozen pond. They push off against one another and the 47.0 kg skater acquires a velocity of 0.645 m/s south. If the other skater has a mass of 50 kg what is their velocity? Solve using the principle of conservation of momentum, not impulse.
To solve this problem using the principle of conservation of momentum. So, the velocity of the second skater is approximately 0.609 m/s in the opposite direction (north).
Given:
Mass of the first skater (m1) = 47.0 kg
Velocity of the first skater (v1) = 0.645 m/s south
Mass of the second skater (m2) = 50 kg
Velocity of the second skater (v2) = ?
According to the principle of conservation of momentum, the total momentum before the interaction is equal to the total momentum after the interaction.
Initial momentum = Final momentum
The initial momentum of the system can be calculated by multiplying the mass of each skater by their respective velocities:
Initial momentum = (m1 * v1) + (m2 * v2)
The final momentum of the system can be calculated by considering that after pushing off against each other, the two skaters move in opposite directions with their respective velocities:
Final momentum = (m1 * (-v1)) + (m2 * v2)
Setting the initial momentum equal to the final momentum, we have:
(m1 * v1) + (m2 * v2) = (m1 * (-v1)) + (m2 * v2)
Rearranging the equation and solving for v2:
2 * (m2 * v2) = m1 * v1 - m1 * (-v1)
2 * (m2 * v2) = m1 * v1 + m1 * v1
2 * (m2 * v2) = 2 * m1 * v1
m2 * v2 = m1 * v1
v2 = (m1 * v1) / m2
Substituting the given values, we can calculate the velocity of the second skater:
v2 = (47.0 kg * 0.645 m/s) / 50 kg
v2 ≈ 0.609 m/s
Therefore, the velocity of the second skater is approximately 0.609 m/s in the opposite direction (north).
To learn more about, momentum, click here, https://brainly.com/question/30677308
#SPJ11
An 76-kg jogger is heading due east at a speed of 3.2 m/s. A 67-kg jogger is heading 56 ∘
north of east at a speed of 2.7 m/s. Find (a) the magnitude and (b) the direction of the sum of the momenta of the two joggers. Describe the direction as an angle with respect to due east.
The magnitude of the sum of the
momenta
can be found using the vector addition of the individual momenta.
The direction of the sum of the momenta can be described as an angle with respect to due east.
(a) To find the
magnitude
of the sum of the momenta, we need to add the individual momenta vectorially.
Momentum of the first jogger (J1):
Magnitude = Mass ×
Velocity
= 76 kg × 3.2 m/s = 243.2 kg·m/s
Momentum of the second jogger (J2):
Magnitude =
Mass
× Velocity = 67 kg × 2.7 m/s = 180.9 kg·m/s
Sum of the momenta (J1 + J2):
Magnitude = 243.2 kg·m/s + 180.9 kg·m/s = 424.1 kg·m/s
Therefore, the magnitude of the sum of the momenta is 424.1 kg·m/s.
(b) To find the direction of the sum of the momenta, we can use
trigonometry
to determine the angle with respect to due east.
Given that the second jogger is heading 56° north of east, we can subtract this angle from 90° to find the direction angle with respect to due east.
Direction angle = 90° - 56° = 34°
Therefore, the direction of the sum of the momenta is 34° with respect to due east.
To learn more about
momenta
click here.
brainly.com/question/32847939
#SPJ11
In class, we derived the time-harmonic Maxwell's equations with (et). Drive here the time-harmonic Maxwell's equations with (et)
Non-dimensionalized Maxwell’s Equations can be represented as follows: 1) i = (ε r E + c = - J + c = 0) where is the unknown electric field and is the known current source.
Maxwell's Equations are a collection of four equations describing the behavior of electrical and magnetic fields. Maxwell's Equations also explain the relationship between electric and magnetic fields.
The time-harmonic Maxwell's equations
∇E = P/ε₀
∇B = 0
∇ E = ∂B/∂t
∇H = J + ∂D/∂t
σ/σt = -iw
∇E = P/E
∇B = 0
∇E = iwB ∇E = iwμh
∇H = J- iwD
∇B = μ₀J - iwμεE
To learn more about the electric field, refer to the link:
https://brainly.com/question/11482745
#SPJ4
cylinder shaped steel beam has a circumference of 3.5
inches. If the ultimate strength of steel is 5 x
10° Pa., what is the maximum load that can be supported by the
beam?"
The maximum load that can be supported by the cylinder-shaped steel beam can be calculated using the ultimate strength of steel and circumference of beam. The maximum load is 4.88 x 10^9 pounds.
The formula for stress is stress = force / area, where force is the load applied and area is the cross-sectional area of the beam. The cross-sectional area of a cylinder is given by the formula A = πr^2, where r is the radius of the cylinder.
To calculate the radius, we can use the circumference formula C = 2πr and solve for r: r = C / (2π).
Substituting the given circumference of 3.5 inches, we have r = 3.5 / (2π) ≈ 0.557 inches.
Next, we calculate the cross-sectional area: A = π(0.557)^2 ≈ 0.976 square inches.
Now, to find the maximum load, we can rearrange the stress formula as force = stress x area. Given the ultimate strength of steel as 5 x 10^9 Pa, we can substitute the values to find the maximum load:
force = (5 x 10^9 Pa) x (0.976 square inches) ≈ 4.88 x 10^9 pounds.
Therefore, the maximum load that can be supported by the beam is approximately 4.88 x 10^9 pounds.
Learn more about cross-sectional area here; brainly.com/question/31308409
#SPJ11
The magnetic field of a plane EM wave is given by B = B0 cos(kz
− ωt)i.
Indicate:
a) The direction of propagation of the wave
b) The direction of E.
Given magnetic field of a plane EM wave is: B = B0cos(kz − ωt)i and we need to find the direction of propagation of the wave and the direction of E.
Let’s discuss this one by one.Direction of propagation of the wave: We can find the direction of propagation of the wave from the magnetic field.
The plane EM wave is propagating along the x-axis as ‘i’ is the unit vector along x-axis. The wave is traveling along the positive x-axis because the cosine function is positive
when kz − ωt = 0 at some x > 0.
Thus, we can say the direction of propagation of the wave is in the positive x-axis.Direction of E: The electric field can be obtained by applying Faraday's Law of Electromagnetic Induction.
We know that E = −dB/dt, where dB/dt is the rate of change of magnetic field w.r.t time. We differentiate the given magnetic field w.r.t time to find the
E.E = - d/dt(B0cos(kz − ωt)i) = B0w*sin(kz − ωt)j
Here, j is the unit vector along the y-axis. As we can see from the equation of electric field, the direction of E is along the positive y-axis. Answer:a) The direction of propagation of the wave is in the positive x-axis.b) The direction of E is along the positive y-axis.
To know more about magnetic visit :
https://brainly.com/question/3617233
#SPJ11
A rock is dropped at time t=0 from a tower 50−m high. 1 second later a second rock is thrown downward from the same height. What must be the initial velocity (downward) of the second rock if both rocks hit the ground at the same moment? 15.4 m/s 9.8 m/s 12 m/s 16 m/s
The initial velocity (downward) of the second rock must be approximately 101 m/s if both rocks hit the ground at the same moment.
We are given that a rock is dropped at time t = 0 from a tower 50 m high. One second later, a second rock is thrown downward from the same height. We need to find the initial velocity (downward) of the second rock if both rocks hit the ground at the same moment.
Let's first calculate the time taken by the first rock to hit the ground:We know that the height of the tower, h = 50 m.Let g = 9.8 m/s² be the acceleration due to gravity.
As the rock is being dropped, its initial velocity u is zero.Let the time taken by the first rock to hit the ground be t₁.
Using the formula: h = ut + (1/2)gt² ,
50 = 0 + (1/2) * 9.8 * t₁²,
0 + (1/2) * 9.8 * t₁² ⇒ t₁ = √(50 / 4.9) ,
t₁ = 3.19 s.
Now let's consider the second rock. Let its initial velocity be u₂.The time taken by the second rock to hit the ground is
t₁ = t₁ - 1 ,
t₁ - 1 = 2.19 s.
We know that the acceleration due to gravity is g = 9.8 m/s².Using the formula: h = ut + (1/2)gt²
50 = u₂(2.19) + (1/2) * 9.8 * (2.19)².
u₂(2.19) + (1/2) * 9.8 * (2.19)²⇒ 245 ,
245 = 2.19u₂ + 22.9,
2.19u₂ + 22.9⇒ 2.19u₂,
2.19u₂= 222.1,
u₂ = 222.1 / 2.19,
u₂ ≈ 101.37,
u₂ ≈ 101 m/s.
Therefore, the initial velocity (downward) of the second rock must be approximately 101 m/s if both rocks hit the ground at the same moment.
Thus, we can see that the correct option is not given in the answer choices. The correct answer is 101 m/s.
To know more about acceleration due to gravity visit:
brainly.com/question/21775164
#SPJ11
In The Provided Circuit, If The Battery EMF Is 4 V, What Is The Power Dissipated At The 9Ω Resistor? (In W)
The power dissipated by the 9 Ω resistor is 0.64 W when the battery EMF is 4V.
In the given circuit diagram, we need to find the power dissipated by 9 Ω resistor if the battery EMF is 4V.
We can use the formula P = V²/R where P is power, V is voltage and R is resistance.
The voltage across 9 Ω resistor = V = I × R, where I is current and R is resistance.
The current flowing through the circuit = I
= V/R (using Ohm’s law)
= 4V/15 Ω
= 0.2666 Amps
The voltage across 9 Ω resistor = V
= I × R
= 0.2666 A × 9 Ω
= 2.4 V
Now, we can find the power dissipated by 9 Ω resistor using the formula:
P = V²/R
= 2.4 V² / 9 Ω
= 0.64 W
Thus, the power dissipated by the 9 Ω resistor is 0.64 W when the battery EMF is 4V.
Learn more about power from the given link
https://brainly.com/question/1634438
#SPJ11
Young's double-sit experiment is performed with 585 nm light and a distance of 2.00 m between the sits and the screen. The tenth interference minimum is observed 7.00 mm from the central maximum. Determine the spacing of the sits (in) 1,60 mm
We can use the formula for the spacing of the slits in Young's double-slit experiment:
d = (m * λ * D) / y
d is the spacing of the slits
m is the order of the interference minimum (in this case, the tenth minimum, so m = 10)
λ is the wavelength of light (in meters)
D is the distance between the slits and the screen (in meters)
y is the distance from the central maximum to the observed interference minimum (in meters)
λ = 585 nm = 585 × 10^(-9) m
D = 2.00 m
y = 7.00 mm = 7.00 × 10^(-3) m
m = 10
Substituting the values into the formula, we have:
d = (10 * 585 × 10^(-9) m * 2.00 m) / (7.00 × 10^(-3) m)
d = 1.60 × 10^(-3) m
spacing of the slits (d) is 1.60 mm.
Learn more about slits
https://brainly.com/question/30890401
#SPJ11
An accelerating voltage of 2.45 x 10³ V is applied to an electron gun, producing a beam of electrons originally traveling horizontally north in vacuum toward the center of a viewing screen 36.6 cm away. (a) What is the magnitude of the deflection on the screen caused by the Earth's gravitational field? (b) What is the direction of the deflection on the screen caused by the Earth's gravitational field? O up O down O east O west (c) What is the magnitude of the deflection on the screen caused by the vertical component of the Earth's magnetic field, taken as 20.0 μT down? mm (d) What is the direction of the deflection on the screen caused by the vertical component of the Earth's magnetic field, taken as 20.0 μT down? O north O south O east O west (e) Does an electron in this vertical magnetic field move as a projectile, with constant vector acceleration perpendicular to a constant northward component of velocity? Yes O No (f) Is it a good approximation to assume it has this projectile motion? Yes O No Explain.
The magnitude of the deflection on the screen caused by the Earth's gravitational field can be calculated as below: F_gravity = m * g, where m = mass of electron, g = acceleration due to gravity = 9.8 m/s².
F_gravity = 9.1 x 10⁻³¹ kg * 9.8 m/s² = 8.91 x 10⁻³⁰ N Force on the electron will be F = q * E, where q = charge on electron = 1.6 x 10⁻¹⁹ C, E = electric field = V / d, where V = accelerating voltage = 2.45 x 10³ V, d = distance from the electron gun to the screen = 36.6 cm = 0.366 m.
E = V / d = 2.45 x 10³ V / 0.366 m = 6.68 x 10³ V/mF = q * E = 1.6 x 10⁻¹⁹ C * 6.68 x 10³ V/m = 1.07 x 10⁻¹⁵ N Force on the electron due to the Earth's gravitational field = F_gravity = 8.91 x 10⁻³⁰ NNet force on the electron = F_net = √(F_gravity² + F²)F_net = √(8.91 x 10⁻³⁰ N)² + (1.07 x 10⁻¹⁵ N)² = 1.07 x 10⁻¹⁵ NAngle of deflection = tan⁻¹(F_gravity / F) = tan⁻¹(8.91 x 10⁻³⁰ / 1.07 x 10⁻¹⁵) = 0.465°Magnitude of deflection = F_net * d / (q * V) = 1.07 x 10⁻¹⁵ N * 0.366 m / (1.6 x 10⁻¹⁹ C * 2.45 x 10³ V) = 1.47 x 10⁻³ mm(b) The direction of the deflection on the screen caused by the Earth's gravitational field is down.
To know more about magnitude visit:
https://brainly.com/question/28714281
#SPJ11
If there was a greater friction in central sheave of the pendulum, how would that influence fall time and calculated inertia of the pendulum? o Fall time decreases, calculated inertia decreases o Fall time decreases, calculated inertia does not change o Fall time decreases, calculated inertia increases o Fall time increases, calculated inertia increases • Fall time increases, calculated inertia does not change o Fall time does not change, calculated inertia decreases
Greater friction in the central sheave of the pendulum would increase fall time and calculated inertia. The moment of inertia of a pendulum is calculated using the following formula: I = m * r^2.
The moment of inertia of a pendulum is calculated using the following formula:
I = m * r^2
where:
I is the moment of inertia
m is the mass of the pendulum
r is the radius of the pendulum
The greater the friction in the central sheave, the more energy is lost to friction during each swing. This means that the pendulum will have less energy to swing back up, and it will take longer to complete a full swing. As a result, the fall time will increase.
The calculated inertia will also increase because the friction will cause the pendulum to act as if it has more mass. This is because the friction will resist the motion of the pendulum, making it more difficult to start and stop.
The following options are incorrect:
Fall time decreases, calculated inertia decreases: This is incorrect because the greater friction will cause the pendulum to have more inertia, which will increase the fall time.
Fall time decreases, but calculated inertia does not change: This is incorrect because the greater friction will cause the pendulum to have more inertia, which will increase the fall time.
Fall time increases, calculated inertia decreases: This is incorrect because the greater friction will cause the pendulum to have more inertia, which will increase the fall time.
Fall time does not change, calculated inertia decreases: This is incorrect because the greater friction will cause the pendulum to have more inertia, which will increase the fall time.
To learn more about the moment of inertia click here
https://brainly.com/question/33002666
#SPJ11
Two teams are having a tug of war. Each team exerts a force of 1500 N. What is the tension in the rope? Explain.
The tension in the rope is 3000 N.
The tension in the rope in a tug of war game can be found out by calculating the resultant force of the two teams pulling the rope. The tension in the rope is the same throughout the entire rope because it is the force being applied by both teams on the rope.
Tension is a force that is developed when a material is pulled or stretched in opposite directions. It is the pulling force applied by a rope or a cable. The tension force is always directed along the length of the rope or cable. Tension is also called tensile force. The tension formula is given as,
Tension (T) = Force (F) / Area (A)
Hence, The tension in the rope during a tug of war game is the sum of the forces applied by both teams. Each team applies a force of 1500 N. So, the resultant force is given as:
Resultant force = Force applied by team 1 + Force applied by team 2= 1500 N + 1500 N= 3000 N
Therefore, the tension in the rope is 3000 N.
Learn more about tension https://brainly.com/question/29466375
#SPJ11
2. Now you try one. Suppose that charge 1 has a magnitude of +6.00μC, charge 2 of +5.00μC, and charge 1 is located at 4.00cm i +3.00cm ĵ and charge 2 is located at 6.00cm î-8.00cm j. Find F12 and
Given information Magnitude of charge 1 = +6.00μCMagnitude of charge 2 = +5.00μCLocation of charge 1 = 4.00cm i +3.00cm j Location of charge 2 = 6.00cm i -8.00cm j Find the force between charge 1 and charge 2.
Force between the two charges is given byF12 = (kq1q2) / r^2Where k is the Coulomb’s constant and is given byk = 9 x 10^9 Nm^2/C^2q1 and q2 are the magnitudes of the charges and r is the distance between the two charges.F12 = (9 x 10^9 Nm^2/C^2) (6.00μC) (5.00μC) / r^2First, find the distance between the two charges.
We know that charge 1 is located at 4.00cm i + 3.00cm j and charge 2 is located at 6.00cm i - 8.00cm j. Distance between the two charges is given byr = √((x₂-x₁)² + (y₂-y₁)²)r = √((6.00 - 4.00)² + (-8.00 - 3.00)²)r = √(2.00² + 11.00²)r = √125r = 11.18cmPutting the value of r in the formula of F12, we haveF12 = (9 x 10^9 Nm^2/C^2) (6.00μC) (5.00μC) / (11.18cm)²F12 = 17.3 x 10^5 NThe force between the two charges is 17.3 x 10^5 N.Answer:F12 = 17.3 x 10^5 N.
To know more about Magnitude visit:
https://brainly.com/question/31022175
#SPJ11
Consider a small object at the center of a glass ball of diameter 28.0cm. Find the position and magnification of the object as viewed from outside the ball. The index of refraction for glass is 1.60. Find the focal point. Is it inside or outside of the ball?Object 28.0 cm
Therefore, the position of the object as viewed from outside the glass ball is approximately 21 cm away from the surface of the ball, and the magnification is approximately -1.5.
To find the position and magnification of the object as viewed from outside the glass ball, we can use the lens equation and the magnification equation.
Diameter of the glass ball (d) = 28.0 cm
Index of refraction of glass (n) = 1.60
First, let's find the focal point of the glass ball. Since the object is at the center of the ball, the focal point will also be at the center.
The focal length of a lens is given by the formula:
f = (n - 1) * R
where f is the focal length and R is the radius of curvature of the lens.
Since the glass ball is a sphere, the radius of curvature is half the diameter:
R = d/2 = 28.0 cm / 2 = 14.0 cm
Substituting the values into the formula, we can find the focal length:
f = (1.60 - 1) * 14.0 cm = 0.60 * 14.0 cm = 8.4 cm
The focal point is located at a distance of 8.4 cm from the center of the glass ball. Since the object is at the center of the ball, the focal point is inside the ball.
Now let's find the position and magnification of the object as viewed from outside the ball.
The lens equation relates the object distance (do), image distance (di), and focal length (f):
1/do + 1/di = 1/f
Since the object is at the center of the ball, the object distance is equal to the radius of the ball:
do = d/2 = 28.0 cm / 2 = 14.0 cm
Substituting the values into the lens equation:
1/14.0 cm + 1/di = 1/8.4 cm
Solving for the image distance (di):
1/di = 1/8.4 cm - 1/14.0 cm
1/di = (14.0 cm - 8.4 cm) / (8.4 cm * 14.0 cm)
1/di = 5.6 cm / (8.4 cm * 14.0 cm)
1/di = 5.6 cm / 117.6 cm^2
di = 117.6 cm^2 / 5.6 cm
di ≈ 21 cm
The image distance (di) is approximately 21 cm.
To find the magnification (m), we can use the formula:
m = -di/do
Substituting the values:
m = -21 cm / 14.0 cm
m ≈ -1.5
The magnification (m) is approximately -1.5, indicating that the image is inverted.
Therefore, the position of the object as viewed from outside the glass ball is approximately 21 cm away from the surface of the ball, and the magnification is approximately -1.5.
Learn more about magnification https://brainly.com/question/131206
#SPJ11
4. What is the velocity change as water goes into a 6.00-cm-diameter nozzle from a 12.00-cm-diameter fire hose while carrying a flow of 50.0 L/s? [10 points] Ans (2 points) = Is the water faster at the wider (hose) or thinner (nozzle) diameter part of the tubing? (3 points total) (1 points) Answer= hose or nozzle Why? (2 points) Given: To Find: Solution: (5 points total)
Water accelerates as it passes through a constriction in a region of the pipe where the cross-sectional area is reduced. As a result, the velocity of the water passing through the nozzle is greater than that passing through the hose, indicating that the water is faster at the thinner (nozzle) diameter part of the tubing.
Diameter of fire hose = 12 cm
Diameter of nozzle = 6 cm
Flow of water = 50 L/s
To Find: Velocity change as water goes into a 6.00-cm-diameter nozzle from a 12.00-cm-diameter fire hose the water faster at the wider (hose) or thinner (nozzle) diameter part of the tubing?
Answer:
Velocity of water flowing through the fire hose, V₁ = (4Q)/(πd₁² )
Where, Q = Flow of water = 50 L/sd₁ = Diameter of fire hose = 12 cm
Putting the given values,V₁ = (4 × 50 × 10⁻³)/(π × 12²) = 0.09036 m/s
Velocity of water flowing through the nozzle, V₂ = (4Q)/(πd₂² )
Where, d₂ = Diameter of nozzle = 6 cm
Putting the given values,V₂ = (4 × 50 × 10⁻³)/(π × 6²) = 0.36144 m/s
Velocity change, ΔV = V₂ - V₁= 0.36144 - 0.09036= 0.2711 m/s
Thus, the velocity change as water goes into a 6.00-cm-diameter nozzle from a 12.00-cm-diameter fire hose while carrying a flow of 50.0 L/s is 0.2711 m/s.
The water is faster at the thinner (nozzle) diameter part of the tubing.
To know more about accelerates visit:
https://brainly.com/question/32899180
#SPJ11
A 4 V battery is connected to a circuit and causes an electric current. 10 C of charge passes between its electrodes + and -. The battery gave them, during their march from one electrode to the other, a total of _ J.
The total energy given by the battery to the electric charge during their march from one electrode to the other is 40 J.
A 4 V battery is connected to a circuit and causes an electric current. 10 C of charge passes between its electrodes + and -. The battery gave them, during their march from one electrode to the other, a total of 40 J. Electric potential difference is known as the potential difference between two points in an electric circuit. Voltage is an energy unit that has potential energy. A battery is an electrochemical device that converts chemical energy into electrical energy. A battery has two electrodes that are the positive and negative terminals, and the flow of electric current is caused by the movement of electrons from one terminal to the other.
The electric charge can be calculated by the formula q = i x t Where,q is the charge in coulombs is the current in ampere is the time in seconds Therefore, for the given values,i = 1 AT = 10 seconds q = i x tq = 1 x 10q = 10 C The electric potential difference between the electrodes is 4 V. The work done by the battery to move 10 C of charge from one electrode to the other can be calculated using the formula W = q x VW = 10 x 4W = 40 J Therefore, the total energy given by the battery to the electric charge during their march from one electrode to the other is 40 J.
To know more about battery visit
https://brainly.com/question/16791263
#SPJ11
Two particles are fixed to an x axis: particle 1 of charge 91 = 1.79 × 10^-8 C at x = 18.0 cm and particle 2 of charge 92 =-3.24g1 at x = 65.0
cm. At what coordinate on the x axis is the electric field produced by the particles equal to zero?
"To find the coordinate on the x-axis where the electric field produced by the particles is equal to zero, we need to calculate the electric field at different points and determine where it becomes zero."
The electric field produced by a point charge at a distance r from the charge is given by the equation:
E = k * (q / r²)
where E is the electric field, k is the electrostatic constant (k = 8.99 x 10⁹ Nm²/C²), q is the charge of the particle, and r is the distance from the particle.
Let's calculate the electric field produced by particle 1 at different points along the x-axis:
For particle 1:
q1 = 1.79 x 10⁻⁸ C
x1 = 18.0 cm = 0.18 m
Now, let's calculate the electric field produced by particle 2 at different points along the x-axis:
For particle 2:
q2 = -3.24 x 10⁻⁹ C
x2 = 65.0 cm = 0.65 m
Now, we can calculate the electric field at a particular point on the x-axis by summing the electric fields produced by both particles:
E_total = E1 + E2
We can set up the equation:
k * (q1 / r1²) + k * (q2 / r2²) = 0
Simplifying the equation:
(q1 / r1²) + (q2 / r2²) = 0
Now, we can solve this equation to find the value of r (the coordinate on the x-axis) where the electric field is equal to zero.
To know more about electrostatic force visit:
https://brainly.com/question/30236242
#SPJ11
A 24 kg object is acted on by three forces. One of the forces is 5.10 N to the east and one is 14.50 N is to the west. (Where east is positive and west is negative.) If the acceleration of the object is -2.00 m/s. What is the third force? Use positive for a force and accelerations directed east, and negative for a force and accelerations going west
We can use Newton's second law of motion, which states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration.
Mass of the object (m) = 24 kg
Acceleration (a) = -2.00 m/s² (negative because it is directed west)
Net force (F_net) = m * a
F_net = 24 kg * (-2.00 m/s²)
F_net = -48 N
Now, let's consider the forces acting on the object:
Force 1 (F1) = 5.10 N to the east (positive force)
Force 2 (F2) = 14.50 N to the west (negative force)
Force 3 (F3) = ? (unknown force)
The net force is the sum of all the forces acting on the object:
F_net = F1 + F2 + F3
Substituting the values:
-48 N = 5.10 N - 14.50 N + F3
To isolate F3, we rearrange the equation:
F3 = -48 N - 5.10 N + 14.50 N
F3 = -38.6 N
Therefore, the third force (F3) is -38.6 N, directed to the west.
Learn more about force
https://brainly.com/question/30507236
#SPJ11
A puck moves on a horizontal air table. It is attached to a string that passes through a hole in the center of the table. As the puck rotates about the hole, the string is pulled downward very slowly and shortens the radius of rotation, so the puck gradually spirals in towards the center. By what factor will the puck's angular speed have changed when the string's length has decreased to one-third of its original length?
The puck's angular speed will increase by a factor of 3 when the string's length has decreased to one-third of its original length.
1. When the string is pulled downward, the puck's radius of rotation decreases, causing it to spiral in towards the center.
2. As the puck moves closer to the center, its moment of inertia decreases due to the shorter distance from the center of rotation.
3. According to the conservation of angular momentum, the product of moment of inertia and angular speed remains constant unless an external torque acts on the system.
4. Initially, the puck's moment of inertia is I₁ and its angular speed is ω₁.
5. When the string's length decreases to one-third of its original length, the puck's moment of inertia reduces to 1/9 of its initial value (I₁/9), assuming the puck's mass remains constant.
6. To maintain the conservation of angular momentum, the angular speed must increase by a factor of 9 to compensate for the decrease in moment of inertia.
7. Therefore, the puck's angular speed will increase by a factor of 3 (9/3) when the string's length has decreased to one-third of its original length.
To know more about angular speed click here:
https://brainly.com/question/29058152
#SPJ11
13) You find an old gaming system in a closet and are eager to let nostalgia take over while you play old games. However, you find that the transformer in the power supply to the system is not working. You read on the console that it requires a 9V AC voltage to work correctly and can be plugged into a standard 120V AC wall socket to get the power. Using your spiffy new physics knowledge, how could you make a transformer that would accomplish the task? (Show any calculations that could be performed.)
To step down the voltage from a standard 120V AC wall socket to the required 9V AC for the gaming system, you can create a transformer with a turns ratio of approximately 1/13.33.
Transformers are devices that use electromagnetic induction to transfer electrical energy between two or more coils of wire. The turns ratio determines how the input voltage is transformed to the output voltage. In this case, we want to step down the voltage, so the turns ratio is calculated by dividing the secondary voltage (9V) by the primary voltage (120V), resulting in a ratio of approximately 1/13.33. To construct the transformer, you would need a suitable core material, such as iron or ferrite, and two separate coils of wire. The primary coil should have around 13.33 turns, while the secondary coil will have 1 turn. When the primary coil is connected to the 120V AC wall socket, the transformer will step down the voltage by the turns ratio, resulting in a 9V output across the secondary coil. This stepped-down voltage can then be used to power the gaming system, allowing you to indulge in nostalgic gaming experiences. It is important to note that designing and constructing transformers require careful consideration of factors such as current ratings, insulation, and safety precautions. Consulting transformer design guidelines or seeking assistance from an experienced electrical engineer is recommended to ensure the transformer is constructed correctly and safely.
To learn more about transformer with a turns ratio, Click here:
https://brainly.com/question/32336838
#SPJ11
Current in a Loop A 32.2 cm diameter coil consists of 16 turns of circular copper wire 2.10 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 8.85E-3 T/s. Determine the current in the loop. Submit Answer Incompatible units. No conversion found between "ohm" and the required units. Tries 0/12 Previous Tries Determine the rate at which thermal energy is produced. Submit Answer Tries 0/12
The current in the loop is 0.11 A and the rate at which thermal energy is produced is 9.4 mW.
Diameter of coil = 32.2 cm = 0.322 m
Number of turns = 16
Diameter of wire = 2.10 mm = 0.0021 m
Resistivity of copper = 1.7 × 10−8 Ω⋅m
Magnetic field change rate = 8.85E-3 T/s
Area of coil = πr2 = 3.14 × 0.161 × 0.161 = 0.093 m2
Magnetic flux = (Number of turns) × (Area of coil) × (Magnetic field change rate)
= 16 × 0.093 × 8.85E-3 = 1.27 T⋅m2/s
Induced emf = (Magnetic flux) / (Time)
= 1.27 T⋅m2/s / 1 s
= 1.27 V
Current = (Induced emf) / (Resistance)
= 1.27 V / 1.7 × 10−8 Ω⋅m
= 0.11 A
Thermal energy produced = (Current)2 × (Resistance)
= (0.11 A)2 × 1.7 × 10−8 Ω⋅m
= 9.4 mW
Learn more about thermal energy with the given link,
https://brainly.com/question/19666326
#SPJ11
The drawing shows a parallel plate capacitor that is moving with a speed of 34 m/s through a 4.3-T magnetic field. The velocity v is perpendicular to the magnetic field. The electric field within the capacitor has a value of 220 N/C, and each plate has an area of 9.3 × 10-4 m2. What is the magnitude of the magnetic force exerted on the positive plate of the capacitor?
The magnitude of the magnetic force exerted on the positive plate of the capacitor is 146.2q N.
In a parallel plate capacitor, the force acting on each plate is given as F = Eq where E is the electric field between the plates and q is the charge on the plate. In this case, the magnetic force on the positive plate will be perpendicular to both the velocity and magnetic fields. Therefore, the formula to calculate the magnetic force is given as F = Bqv where B is the magnetic field, q is the charge on the plate, and v is the velocity of the plate perpendicular to the magnetic field. Here, we need to find the magnetic force on the positive plate of the capacitor.The magnitude
of the magnetic force exerted on the positive plate of the capacitor. The formula to calculate the magnetic force is given as F = BqvWhere, B = 4.3 T, q is the charge on the plate = q is not given, and v = 34 m/s.The magnetic force on the positive plate of the capacitor will be perpendicular to both the velocity and magnetic fields. Therefore, the magnetic force exerted on the positive plate of the capacitor can be given as F = Bqv = (4.3 T)(q)(34 m/s) = 146.2q N
to know more about capacitors here:
brainly.com/question/31627158
#SPJ11