Answer:
the correct answer is C
Explanation:
For this exercise we can use the conservation of angular momentum, let's define a system formed by the disk and the other body, so that the torques during the collision have been internal and the moment is conserved.
Initial instant. Before placing the second body
L₀ = I₁ w₁
Final moment. Right after placing the body
L_f = (I₁ + I₂) w
the moment of inertia of the ring with respect to an axis passing through its center is tabulated
I_{cm} = m r²
we use the parallel axes theorem to find the moment of inertia about an axis passing through one end
I₁ = I_{cm} + m d²
where d is the distance from the center of mass to the new axis
d = r / 2
we substitute
I₁ = mr² + m (r/2)²
I₁ = 5/4 m r²
The second body does not specify a specific shape, so we can assume it to be punctual
I₂ = m’ (2r)²
I₂ = 4 m’ r²
in the exercise indicate that
m ’= m / 4
I₂ = m r²
how the moment of inertia is conserved
L₀ = L_f
I₁ w₁ = (I₁ + I₂) w
5/4 m r² w₁ = (5/4 m r² + m r²) w
5/4 m r² w₁ =9/4 m r² w
w = 5/9 w₁
we calculate
w = 5/9 12
w = 6.67 rad / s
having the initial and final angular velocities we can find the kinetic energy of the hoop
K₀ = ½ I₁ w₁²
K_f = ½ (I₁) w2
the energy ratio is
[tex]\frac{K_f}{K_o}[/tex] = [tex]\frac{w^2}{w_1^2}[/tex]
\frac{K_f}{K_o} = (6.67 / 12)²
\frac{K_f}{K_o} = 0.309
[tex]\frac{K_f}{K_o} %[/tex] = 31%
the correct answer is C
It's your birthday, and to celebrate you're going to make your first bungee jump. You stand on a bridge 100m above a raging river and attach a 35-m-long bungee cord to your harness. A bungee cord, for practical purposes, is just a long spring, and this cord has a spring constant of 43N/m . Assume that your mass is 79kg . After a long hesitation, you dive off the bridge. How far are you above the water when the cord reaches its maximum elongation? h=
Answer:
h = 47 m
Explanation:
First, we will calculate the force on the cord due to the weight:
[tex]Force = F = Weight\\F = mg\\F = (79\ kg)(9.81\ m/s^2)\\F = 775\ N[/tex]
Now, we will calculate the elongation by using Hooke's Law:
[tex]F = k \Delta x[/tex]
where,
k = spring constant = 43 N/m
Δx = elongation = ?
Therefore,
[tex]775\ N = (43\ N/m)\Delta x\\\\\Delta x = \frac{775\ N}{43\ N/m}\\\\\Delta x = 18\ m\\[/tex]
So, the final length of the cord will be:
[tex]Final\ Length = Initial\ Length + \Delta x\\Final\ Length = 35\ m + 18\ m\\Final\ Length = 53\ m\\[/tex]
Hence, the height from water (h) can be found using the following formula:
[tex]h = Height\ of\ Bridge - Final\ Length\ of\ cord\\h = 100\ m - 53\ m\\[/tex]
h = 47 m
A potter's wheel is a uniform disk of mass 4.50 kg and radius 0.650 m and can spin freely around a vertical axis through its center. With the wheel spinning at an angular speed of 4.70 rad/s, a small piece of clay of mass 0.870 kg is dropped at the outer edge of the wheel and sticks to it. Find the final angular speed of the wheel clay. Treat the piece of clay as a point particle. Group of answer choices
Answer:
3.39 rad / s.
Explanation:
Given data:
mass of disk = 4.50 Kg
radius of wheel = 0.650 m
mass of the clay = 0.870 kg
The moment of inertial of the wheel = I = 4.5 kg x ( 0.65 m )2 / 2 = 0.95 kg . m2.
Now, applying the principle of angular momentum conservation :
Iω_i = ( I + mr2 )ω_f.
where ω_i = initial angular speed= 4.70 rad/s, ω_f = final angular speed
Hence, ω_f = Iω_i / ( I + mr2 )
= ( 0.95 kg . m2 x 4.7 rad / s ) / [ 0.95 kg . m2 + 0.87 kg x ( 0.65 m )2 ]
= 3.39 rad / s.
Hence, correct answer is : 3.39 rad / s.
HELP ITS DUE IN 4 MINUTES
Answer:
the nephew
Explanation:
because we need to First find the trails that is on top of all the others in order to find who was the last to leave, since the person that was last to leave would most likely step on another person's trail that has been theirs before them.
by looking at this picture I noticed that the butler's footprint was the latest one but the dogs footprint steps over it therefore making it the last to leave, and the person who owns a dog is her nephew so therefore the nephew is the one that stole the butterfly trophy.
Which planet is least like earth? Mars,Venus, or Jupiter
Answer:
mars, reason why is because they both are diff from the size
Explanation:
difference between ferromagnetic and antiferromagnetic ..
Answer:
ferromagnetic materials are materials that are highly attracted to magnets while antiferromagnetic materials are materials that are not attracted by magnets
Why is the city of Hoboken, NJ (20 minutes from Newark) and other coastal cities in the United suing ExxonMobile?
Answer:
is that youuuuuuu? fine.
Equation for Specific latent heat
When a helicopter flies, what
type of energy is it using?
A. Thermal energy
B. Mechanical energy
C. Electromagnetic energy
Answer: B. Mechanical energy
Explanation: "Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy (stored energy of position)."
"Potential and kinetic energy of an object as it is stored and moved. Examples of MECHANICAL ENERGY- roller coasters, hydraulic lift, bow and arrow, and helicopters. Helicopters, cars, roller coasters, all moving objects that are being acted on by a force."
Incorrect options: A. Thermal energy and B. Electromagnetic energy. (explanation on both below)
"Thermal energy (also called heat energy) is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other. The energy that comes from the temperature of the heated substance is called thermal energy."
"Electromagnetic radiation, in classical physics, the flow of energy at the universal speed of light through free space or through a material medium in the form of the electric and magnetic fields that make up electromagnetic waves such as radio waves, visible light, and gamma rays."
An ant crawls in a straight line at a constant speed of 0.24 m/s for a distance of 3.0 m, beginning in the corner of a square classroom. It then turns exactly 90 degrees to the right, and proceeds an additional 4.0 m, reaching the far corner of the same wall from which it began. If the second leg of the journey was crawled in half the amount of time as the first, what was the ant's average speed for the whole trip?
Answer:
vavg = 0.37 m/s
Explanation:
The average speed is just the relationship between the total distance traveled, and the total time required for that travel , as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} (1)[/tex]
We know that for the first leg of the journey, the ant crawls at a constant speed of 0.24 m/s, moving 3.0 m.We can find the time required for this part, just applying the definition of average velocity, and solving for the time t (which we will call t₁), as follows:[tex]t_{1} =\frac{x_{1}}{v_{1} } = \frac{3.0m}{0.24m/s} = 12.5 s (2)[/tex]
From the givens, we know that the time for the second part is exactly the half of the value found in (2), so we can write the total time Δt as follows:[tex]\Delta t = t_{1} + \frac{t_{1} }{2} = 12.5 s + 6.25 s = 18.75 s (3)[/tex]
We also know that in the second leg of the journey, the ant traveled 4.0 m, which adds to the 3.0 m of the first part, making a total distance of 7.0 m.Per definition of average speed, we can write the following expression as in (1) replacing Δx and Δt by their values, as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} = \frac{7.0m}{18.75m} = 0.37 m/s (4)[/tex]
An amateur blacksmith wants to cool off a 42kg glowing piece of iron, specific heat 470and decides to toss it into a 5.0 kg iron bucket with 10.0 kg of room temperature(23 C) water in it. To his surprise the water completely evaporates away (meaning once it vaporizes it is no longer part of the system) and after some time he goes to pick up the bucket but finds that the bucket is at 150 C.
Required:
What was the initial temperature of the glowing piece of iron?
Answer:
The right approach is "1479°C".
Explanation:
The given values are:
Mass of iron piece,
[tex]m_p=42 \ kg[/tex]
Mass of iron bucket,
[tex]m_I=5 \ kg[/tex]
Mass of water,
[tex]m_w=10 \ kg[/tex]
Iron's specific heat,
[tex]C_I=470 \ J/Kg^{\circ}C[/tex]
Water's specific heat,
[tex]C_w=4186 \ J/Kg^{\circ}C[/tex]
Initial temperature,
[tex]t_I=23^{\circ}C[/tex]
Final equilibrium temperature,
[tex]T=150^{\circ}C[/tex]
Latent heat,
[tex]L_v=2260\times 10^3 \ J/Kg[/tex]
As we know,
The heat lost by the glowing piece of iron will be equal to the heat gain by the iron bucket as well as water, then
⇒ [tex]m_IC_I \Delta T=m_wC_w(100-23)+m_wL_v+m_bC_I(150-23)[/tex]
On substituting the given values, we get
⇒ [tex]42\times 420\times \Delta T=10\times 4186(100-23)+10(2260\times 10^3)+5\times 420(150-23)[/tex]
⇒ [tex]17640 \Delta T=3.22\times 10^6+2.26\times 10^7+2.667\times 10^5[/tex]
⇒ [tex]\Delta T=\frac{2.60867\times 10^7}{17640}[/tex]
⇒ [tex]\Delta T=1479^{\circ}C[/tex]
Can someone please help me with this !!!!
Answer:
I'm not sure but I think it's 4.5 v
A graduated beaker with 375 mL of water is sitting on a scale which measures the weight of the glass and water to be 7.60 N. When a rock is put into the glass, the volume level of the water changes to 450 mL and the scale reading changes to 9.22 N. What is the specific gravity of the rock
Answer:
Volume of water displaced = 450 - 375 = 75 ml
Vr = volume of rock = 75 ml
Wr = 9.22 - 7.60 = 1.62 N weight of 75 ml of rock
Density of rock = 1.62 N / 75 ml = .0216 N / ml
Density of water = 1000 g / 1000 ml = 9.8 N / 1000 ml = .0098 N / ml
Density of rock / density of water = .0216 / .0098 = 2.20
The specific gravity of the rock in the given water volume is 0.2.
The given parameters;
initial volume of the water, = 375 mlweight of the water, = 7.6 Nfinal volume of water = 450 mlchange in scale reading = 9.22 NThe specific gravity of the rock is calculated as follows;
[tex]S.G = \frac{weight \ in \ air}{Weight \ in \ water} \\\\S.G = \frac{450 - 375}{375} \\\\S.G = 0.2[/tex]
Thus, the specific gravity of the rock in the given water volume is 0.2.
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A yo-yo is twirled in a horizontal circle on a 2 meter long string at 4 m/s. Calculate the speed of the yo-yo if it has the same rotational speed but only 0.5 meters long.
The chemical energy in your food is
transformed into what type of energy in
your moving muscles?
A. Light
B. Mechanical
C. Sound
D. Electromagnetic
Answer:
Electromanetic
Explanation:ESPERO TE AYUDE
1. Describe the components of the reflex arc
Which of the following statements is NOT correct about sea breezes?
A) In a sea breeze, the sand is much warmer than the water, therefore creating a low pressure above the sand.
B) The breeze/wind moves from the sea to the land.
C) The breeze/wind moves from the land to the sea.
D) There is high pressure above the sea, and low pressure above the sand.
The breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
What is sea breeze?Local wind patterns known as sea breezes flow from the sea to land during the day. When there is no strong large-scale wind system and it is very hot or very cold during the day or at night, sea breezes and land breezes alternate along the coasts of large lakes or oceans.
Because the sea breeze's surface flow ends over land, an area of low-level air convergence is created. Locally, this convergence frequently causes air to rise, which promotes the formation of clouds. Showers over land in the afternoon may result from such clouds.
Hence, the sea breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
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the radius of earth is about 6.38 x10^3 km. A 7.20 x10^3 N spacecraft travels away from earth. What is the weight of the spacecraft at the following distances from Earth's surface? a) 6.38 x 10^3 km
Answer:
[tex]1796.65\ \text{N}[/tex]
Explanation:
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
w = Weight of spracecraft at the surface = [tex]7.2\times10^3\ \text{N}[/tex]
m = Mass of spracecraft
R = Radius of Earth = [tex]6.38\times10^3\ \text{km}[/tex]
h = Elevation = [tex]6.38\times10^3\ \text{km}[/tex]
G = Gravitational constant = [tex]6.674\times 10^{-11}\ \text{Nm}^2/\text{kg}^2[/tex]
M = Mass of Earth = [tex]5.972\times 10^{24}\ \text{kg}[/tex]
[tex]w=mg\\\Rightarrow m=\dfrac{w}{g}\\\Rightarrow m=\dfrac{7.2\times 10^3}{9.81}\\\Rightarrow m=733.94\ \text{kg}[/tex]
From the gravitational law we have
[tex]w'=\dfrac{GMm}{(r+h)^2}\\\Rightarrow w'=\dfrac{6.674\times10^{-11}\times 5.972\times 10^{24}\times 733.94}{(6.38\times10^6+6.38\times10^6)^2}\\\Rightarrow w'=1796.65\ \text{N}[/tex]
The weight of the spacecraft at the given height is [tex]1796.65\ \text{N}[/tex]
Select the correct answer.
Which theory was first proposed by Albert Einstein?
OA. the theory of special relativity
O B. the theory of universal gravitation
c. the theory of inertia
OD. the theory of radioactivity
Answer:
A. the theory of special relativity.
Explanation:
The theory of special relativity was first proposed theory by Albert Einstein.
Hope it will help :)❤
What kind of weather would MOST LIKELY lead to hurricane formation?
Answer:
The recipe for a hurricane is a combination of warm, humid wind over tropical waters. The temperature of tropical waters must be at least 80 degrees F for up to 165 feet below the ocean’s surface. As this warm water meets the wind that blows west from Africa across the ocean, it causes the water to vaporize. The water vapor then rises into the atmosphere, where it cools and liquefies.
Explanation:
I hope this helps
A thermionic tube with only a cathode and an anode is called?
What happens during rusting?
Answer:
when water hits a metal surface it alongside oxygen have a chemical reaction making Hydrogenated Iron Oxide
Explanation:
what i remember from 7th grade
You measure the pressure of the four tires of your car each to be 35.0 pounds per square inch (psi). You then roll your car forward so that each tire is upon a sheet of paper. You outline the surface area of contact between each tire and the paper, which you later measure to be 32.0 square inches. What is the weight of your car
Answer:
Weight of car = 36034.88 lb.ft/s²
Explanation:
We are told the pressure of the four tires of your car is; P = 35.0 psi
Also, the surface area of contact is; A = 32 in²
Thus;
Weight of tires = Pressure × Area
W_tires = 35 × 32
Weight_tires = 1120lb.
To get the weight of the car, we will multiply the tire weight by acceleration due to gravity.
It's value in ft/s² is g = 32.174 ft/s²
Thus;
Weight of car = 1120 × 32.174
Weight of car = 36034.88 lb.ft/s²
identify the types of motion in each activity.1.walking a long a hallway. 2.motion of the blades of the fan. 3.earths rotation 4.ball moving on the ground. 5.soldiers marching.
Answer:
1) Linear motion
2) Rotational motion
3) Rotational Motion
4) Random Motion ( The ball can be rolling in any direction)
5) Linear motion
The types of motion in each activity include the following:
Walking a long a hallway- Linear motion Motion of the blades of the fan- Rotational motionEarths rotation- Rotational motion Ball moving on the ground- Random motion Soldiers marching- Linear motion.What is Motion?
This involves an object or a body changing position over time. There are
different types of motion with different examples as can be seen above in
this scenario.
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Which of the following represents a concave lens?
A. -di
B. +di
C. -f
D. +f
Answer:
The answer is option D. +f
Option D represents a concave lens. There are two types of lenses, one is a concave lens while the other is the convex lens.
What is the definition of a concave lens?A concave lens deviates a direct beam from the source into a reduced form. At minimum, one interior face of concave lenses is curved.
Because it is curved round inwards at the center and bulges outwards through the edges, causing the light to diverge, a concave lens is also known as a diverging lens.
It forms an upright , virtual picture both real and virtual pictures are formed from the concave lens.
The image formed from the positive side of the focus of the lens.+f shows the positive side of the focus of the lens.f is the focal length.
Hence, option D represents a concave lens
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Background information:
We know that power is the rate that work is done; what that
really means is that power tells up how much work is done every
second. To calculate power we just divide the amount of work that
was done by the time it took to do it (Power=work/time). Work is
measured in Joules and time is measured in seconds, we end up with Joules/sec when we calculate power. A Joule/sec is a Watt; we’ll use Watts to measure and compare power.
We also know that the work done on an object is the amount of energy it has gained. For this activity, you’ll be raising your body up as you do pushups which means you’ll be giving your body gravitational potential energy (GPE). To calculate the amount of GPE we multiply mass time gravity times the height raised (GPE=mgh).
What to do (record everything in the table):
1. You need to have a decent estimate of your mass in kilograms: On earth, every
kilogram weighs 2.2 pounds. Either measure your weight on a scale or just
estimate it (in pounds) then divide by 2.2 to get your mass in kilograms.
2. Measure or estimate the length of your upper arm from your elbow to your
shoulder in centimeters...this is how high you raise yourself for every pushup.
3. Decide if you’ll do regular pushups (on your toes) or simpler pushups (knees). If
you are doing regular pushups, multiply your mass by 0.68 because you’ll only be lifting about 68% of your mass each time; if you’re doing simpler pushups, multiply your mass by 0.52 because you’ll only be lifting about 52% of your mass each time.
4. Measure the time it takes for you to do 10 pushups.
Answer:
Power is the rate at which work is done. It is the work/time ratio. Mathematically, it is computed using the following equation. The standard metric unit of power is the Watt.
Explanation:
Archimedes' Principle states that a. the velocity of a fluid is directly proportional to the pressure exerted on the fluid. b. the pressure of a fluid is inversely proportional to the temperature of the fluid. c. the pressure in a fluid is directly related to the depth below the surface of the fluid. d. an object immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid.
Answer:
d. an object immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid.
A net force of –8750N is used to stop of 1250.kg car travelling 25m/s. What braking distance is needed to bring the car to a halt?
Answer:
d = 44.64 m
Explanation:
Given that,
Net force acting on the car, F = -8750 N
The mass of the car, m = 1250 kg
Initial speed of the car, u = 25 m/s
Final speed, v = 0 (it stops)
The formula for the net force is :
F = ma
a is acceleration of the car
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{-8750}{1250}\\\\a=-7\ m/s^2[/tex]
Let d be the breaking distance. It can be calculated using third equation of motion as :
[tex]v^2-u^2=2ad\\\\d=\dfrac{v^2-u^2}{2a}\\\\d=\dfrac{0^2-(25)^2}{2\times (-7)}\\\\d=44.64\ m[/tex]
So, the required distance covered by the car is 44.64 m.
A submarine is 309 m horizontally from the shore of a freshwater lake and 105 m beneath the surface of the water. A laser beam is sent from the submarine so that the beam strikes the surface of the water 227 m from the shore. A building stands on the shore, and the laser beam hits a target at the top of the building. The goal is to find the height of the target above sea level.
Required:
a. Draw a diagram of the situation, Identifying the two triangles that are important in finding the solution.
b. Find the angle of incidence of the beam striking the water-air interface.
c. Find the angle of refraction.
d. What angle does the refracted beam make with the horizontal?
e. Find the height of the target above sea level.
Answer:
Explanation:
a) See the attached file for diagram . The two triangles are ABC and DEC .
b )
Angle of incidence = i
Tan i = ( 309 - 227 ) / 105
= 82 / 105 = .78
i = 38°
c )
Sin i / sinr = 1 / μ where μ is refractive index of water .
Sin i / sinr = 1 / μ = 1 / 1.33
sin 38 / sinr = .7518
.6156 / sinr = .7518
sinr = .6156 / .7518
.819
r = 55°
d )
angle the refracted beam makes with the horizontal = 90 - 55 = 35°
e )
h / 227 = Tan 35
h = 227 x Tan 35
= 159 m
Height required = 159 m .
can someone help me with science:
The cells within a multicellular organism are of a uniform shape.
True
or False
Answer:
trur
Explanation:
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Mrs. Archer spent her Saturday running a bunch of errands. She started out by
traveling 2 km east, then 5 km south, 12 km east, 2 km south then 40 km west, 60
km north. Calculate her displacement on the Y AXIS.
Answer:
Velocity = displacement/time whereas speed is distance/time. use the formula
Explanation: