Answer: the rarest element is Francium. J is not on the periodic table. also Dmitri Mendeleev proposed the periodic table.
Explanation: Kinda looked the last one up.
Solid pressure depends on?
Answer:
The pressure of the solid on the surface depends on the area of contact. The area of contact between the two surfaces. The greater the force or the smaller the area the greater the pressure.
(credits to the rightful owner for these answers :)
You are standing outside with two speakers. The temperature is 0 degrees C. The two speakers are playing sound of the same frequency: a pure sinusoidal sound of the same frequency at the same phase. The speakers are playing at different amplitudes. One speaker is 1.230 meters from you and one is 1.425 meters from you. You hear no sound. Which of the following is a possible frequency of the sound being played?
a. 993 Hz
b. 331 Hz
c. 4965 Hz
d. 1655 Hz
e. 662 Hz
Answer:
Explanation:
No sound is heard , that means there is destructive interference at the place where sound is heard .
Path difference of the source of sound = 1.425 m - 1.230 m
= 0.195 m
Let frequency of sound be n .
wave length = velocity of sound at 0°C / n
λ = 330 / n
for destructive interference ,
path difference = ( 2m+1) λ /2 , where λ is wave length of sound.
0.195 m = ( 2m+1) λ /2
0.195 m = ( 2m+1)330 / 2n
2n = 1692.3 (2m+1)
If m = 0
n = 846 . which is nearest to given frequency of 993 Hz
So 993 Hz is the answer.
If the frequency of a wave is doubled, what happens to that waves energy
Answer:
If the frequency of a wave is doubled, what happens to its wavelength? If the frequency is doubled, the wavelength is only half as long. 3. ... As the frequency slows down, the wavelength increases.
Explanation:
find a vector length of 5m in the xy plane that is perpendicular to A=3i+6j+2k hint use dot product
Answer:
Explanation:
vector A =(3i^+4J^-2k^),
let the required vector is B = x i^ + y j^
sqrt (x2 + y2) = 5,
x2 + y2 = 25 ..............(1)
Since vector A and B are perpendicular to each other then,
A.B = 0
3x + 4 y = 0
y = -3x/4 ..............(2)
Solving these two equations we get x = 4 and y = -3;
hence vector B = 4 i^ -3 j^
A mass is hung from a vertical spring and allowed to come to rest or its equilibrium position. The mass is then pulled down an additional 0.5 m and released. As the mass oscillates, it completes one full cycle in 5.0 s . Using the given values, correctly identify the mass's amplitude, full range of vertical motion, frequency, and period. The full range of vertical motion is the distance between the maximum and minimum heights of the mass.
The amplitude of the spring is m.
The full range of vertical motion is m.
The frequency of the spring is Hz.
The period of the spring is s.
Explanation:
Given that,
The mass pulled down an additional 0.5 m and released.
The period of oscillation is 5 s
(a) The amplitude of the spring is equal to the maximum displacement i.e. 0.5 m.
(b) The full range of the vertical motion is (2×0.5) = 1 m.
(c) The frequency of the spring,
[tex]f=\dfrac{1}{T}\\\\=\dfrac{1}{5}\\\\=0.2\ Hz[/tex]
(d) The period of the spring is 5 seconds.
A 76 kg boater, initially at rest in a stationary 45 kg boat, steps out of the boat and onto the dock. If the
boater moves out of the boat with a velocity of 2.5 m/s to the right, what is the final velocity of the boat?
The final velocity of the boat is 4.22 m/s in opposite direction to the boater.
Final velocity of the boatThe final velocity of the boat is determined by applying the principle of conservation of linear momentum as follows;
Let the initial velocity of the boater and the boat = v
[tex]m_1 u_1 + m_2 u_2 = v(m_1 + m_2)\\\\76(2.5) + 45u_2 = 0(76 + 45)\\\\190 + 45u_2=0\\\\45u_2 = -190\\\\u_2 = \frac{-190}{45} \\\\u_2 = -4.22 \ m/s[/tex]
Thus, the final velocity of the boat is 4.22 m/s in opposite direction to the boater.
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Two car collide in an intersection. The speed limit in that zone is 30 mph. The car (mass of 1250 kg) was going 17.4 m/s (38.9). The truck (2020 kg) t-boned the car in the middle of the intersection. The car was slowed down to only 6.7 m/s. The truck after colliding with the car was going 10.3 m/s. How fast did the truck go into the intersection?
Answer:
u₂ = 3.7 m/s
Explanation:
Here, we use the law of conservation of momentum, as follows:
[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\[/tex]
where,
m₁ = mass of the car = 1250 kg
m₂ = mass of the truck = 2020 kg
u₁ = initial speed of the car before collision = 17.4 m/s
u₂ = initial speed of the tuck before collision = ?
v₁ = final speed of the car after collision = 6.7 m/s
v₂ = final speed of the truck after collision = 10.3 m/s
Therefore,
[tex](1250\ kg)(17.4\ m/s)+(2020\ kg)(u_2)=(1250\ kg)(6.7\ m/s)+(2020\ kg)(10.3\ m/s)\\\\(2020\ kg)(u_2) = 8375\ N.s + 20806\ N.s - 21750\ N.s\\\\u_2=\frac{7431\ N.s}{2020\ kg}[/tex]
u₂ = 3.7 m/s
Pre-laboratory Assignment: Experiment 20 Reflection and Refraction of Light 1. When light is incident on a reflective surface, what can be said about the angle and speed at which the light is reflected? (Information is in your ‘General Physics Laboratory Manual’ Chapt. 20) 2. At what angle is the normal drawn to the reflective surface or air-medium interface? 3. How are angles of incidence, angles of reflection and of refraction measured? 4. Describe what happens to a light ray as it enters from a medium of greater refractive index to a medium of lesser refractive index
Answer:
1) ngle of incidence and reflection are equal, light carries does not change
2) the angle of this line with respect to the surface is 90º
3) protractor
4) n₂ sin θ₂ = n_1 sin θ₁, light ray must have a greater angle than the incident ray ,
Explanation:
1) When light falls on a reflective surface, the angle of incidence and reflection are equal and as it travels in the same medium, the speed that the light carries does not change
2) The normal is a line perpendicular to the point of incidence of light, so the angle of this line with respect to the surface is 90º
3) Angles are measured with a protractor
4) When light passes from one medium to another, the speed of the ray changes due to the difference in the refractive index in each medium, due to this change in speed the transmitted light ray must have a greater angle than the incident ray , since the speed increases as the density of the medium decreases
[tex]\frac{sin \theta _2}{ sin \theta_1} = \frac{v_2}{v_1}[/tex]
[tex]\frac{c}{v_2} \ sin \theta_2 = \frac{c}{v_1} \ sin \theta_1[/tex]
n₂ sin θ₂ = n_1 sin θ₁
im back and need help
Always here to help. Bring it!!!
Which of the following rays is NOT possible for a converging lens?
Ray B. isn't possible for a converging lens, because after passing through focus ot would go parallel to the principal axis,
So, Correct option is :
=》Option B.)
A 3 kg block is attached to a vertical spring. Initially, you exert a 50 N downwards force on the block, holding it in place, at rest. You let go. Find the instantaneous acceleration of the block immediately after you let go. What is the direction of the acceleration
As you were holding the block down and in place, the spring exerted an upward force that balanced the downward push by your hand and its own weight. So this restoring force has a magnitude of R such that
R - 50 N - (3 kg) g = 0 => R = 79.4 N
As soon as you remove your hand, the block has acceleration a such that, by Newton's second law,
R - (3 kg) g = (3 kg) a => a = (79.4 N - (3 kg) g) / (3 kg) ≈ 16.7 m/s^2
pointing upward.
gayle cooks a roast in her microwave oven. the klystron tube in the oven emits photons whose energy is 1.20 x 10^-3 ev. what are the wavelengths of these photons
Answer:
[tex]\lambda=1.03\times 10^{-3}\ m[/tex]
Explanation:
Given that,
The energy of the microwave oven is [tex]1.2\times 10^{-3}\ eV[/tex].
We need to find the wavelength of these photons.
[tex]1.2\times 10^{-3}\ eV=1.2\times 10^{-3}\times 1.6\times 10^{-19}\\\\=1.92\times 10^{-22}\ J[/tex]
The energy of a wave is given by :
[tex]E=\dfrac{hc}{\lambda}\\\\\lambda=\dfrac{hc}{E}[/tex]
Put all the values,
[tex]\lambda=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{1.92\times 10^{-22}}\\\\\lambda=1.03\times 10^{-3}\ m[/tex]
So, the wavelength of these photon is [tex]1.03\times 10^{-3}\ m[/tex].
Four point masses are connected by rods of negligible mass and form a square with sides of length 32.2 cm. Three of the masses are 1.5 kg and one is 3.0 kg. How far from the 3.0 kg mass is the center of mass of the system
Solution :
Placing the[tex]$3 \ kg$[/tex] mass at the [tex]$\text{origin}$[/tex] and line up the square up with the axes.
[tex]$x_{cm} = \frac{\sum_i x_i m_i}{\sum_i m_i }$[/tex]
[tex]$=\frac{1.5 a + 1.5a +0 +0}{7.5}$[/tex]
[tex]$=\frac{3a}{7.5}$[/tex]
[tex]$=\frac{2a}{5}$[/tex]
[tex]$y_{cm} = \frac{\sum_i y_i m_i}{\sum_i m_i }$[/tex]
[tex]$=\frac{1.5 a + 1.5a +0 +0}{7.5}$[/tex]
[tex]$=\frac{3a}{7.5}$[/tex]
[tex]$=\frac{2a}{5}$[/tex]
Therefore, r = [tex]$\sqrt2 \left(\frac{2a}{5}\right)$[/tex]
[tex]$=\frac{2 \sqrt2}{5}a$[/tex]
It s given that the side of the square is a = 32.2 cm
So, r [tex]$=\frac{2 \sqrt2}{5}a$[/tex]
[tex]$=\frac{2 \sqrt2}{5}\times 32.2$[/tex]
= 18.21 cm
So the distance of the 3 kg mass from the center of mass, r= 18.21 cm
When a massive star greater than 8 solar masses has its core filled with iron, the core can no longer continue fusion, and it becomes supported by electron degeneracy pressure for a while. When the mass of the accumulating iron becomes greater than 1.4 solar masses, what happens
If the hairdryer was put on full power, what would happen? Why?
Most hair dryers are in the 1800 watt range and lets assume you turned it to the highest speed and heat setting.
PLEASE MARK AS A BRAINLISTIt will heat up the air in the box, failry quickly. Rules of thermodynamics says that the heat will increase the temperature according to the rate of heat input minus the rate of heat loss from the box… due to conduction, radiation and convection (in this case none of the latter because the box is sealed).
HOPE IT WILL HELP YOUThe loss rate depends in the temperature difference and the thermal resistance. THicker and better insulation increases the resistance; larger area decreases the resistance. Eventually the heat (temperature) will rise and the difference between inside and outside will be so large that the temperature will rise no more. But in the case of a 1800 W hairdryer the temperature will exceed the melting point of plastics and wire insulation and if allowed to come to heat equilibrium will probably short out and catch fire or blow an external fuse.
Most modern hair dryers have a internal thermal fuse that cuts out at temperatures below the melting point and probably this will cut off the dryer before catastrophic meltdown. Its a one time fuse and not readily available, mostly you toss the dryer when the fuse goes
State the
the properties of magnets.
Answer:
All magnets have two poles: the North Pole and the South Pole.
Magnets attract ferromagnetic materials such as iron, nickel, and cobalt.
The magnetic force of a magnet is stronger at its poles than in the middle.
A freely suspended magnet always points in North-South direction.
Hope this helps
A hydraulic system is lifting a 11760 N car using a cylinder with an area of 0.25 m
squared. What force is applied to the small cylinder if it has an area of 0.0125 m
squared?
Answer: 588 N
Explanation: pressure = force/area, or p = F/A. Then p1=p2
And F1//A1 = F2/A2 . F2 = F1·A2/A1 = 11760 N·0.0125 m²/ 0.25 m²
oscillating spring mass systems can be used to experimentally determine an unknown mass without using a mass balance. a student observes that a particular spring-mass system has a frequency of oscillation of 10 Hz. the spring constant of the spring is 250 N/m. what is the mass?
Answer:
Mass, m = 6.18 kg
Explanation:
Given the following data;
Frequency, F = 10 Hz
Spring constant, k = 250 N/m
We know that pie, π = 22/7
To find the mass, we would use the following formula;
F = 1/2π√(k/m)
Where;
F is the frequency of oscillation.
k is the spring constant.
m is the mass of the spring.
Substituting into the formula, we have;
10 = 1/2 * 22/7 * √250/m
10 = 22/14 * √250/m
Cross-multiplying, we have;
140 = 22 * √250/m
Dividing both sides by 22, we have;
140/22 = √250/m
6.36 = √250/m
Taking the square of both sides, we have;
6.36² = (√250/m)²
40.45 = 250/m
Cross-multiplying, we have;
40.45m = 250
Mass, m = 250/40.45
Mass, m = 6.18 kg
Claire pushes a box to the left while Jamie pushes the same box to the right. The box stays in
between them in the same position.
Which best explains why Claire and Jamie are unable to move the box?
A. They are applying an unbalanced force.
B. They are applying a balanced force.
C. They are applying gravity.
D. They are applying friction.
After landing on an unfamiliar planet, a space explorer constructs a simple pendulum of length 48.0 cm . The explorer finds that the pendulum completes 93.0 full swing cycles in a time of 141 s.
Required:
What is the value of g on this planet?
Answer:
8.24 m/s²
Explanation:
Applying,
T = 2π√(L/g).................... Equation 1
Where T = period of the pendulum, L = Length of the pendulum, g = acceleration due to gravity of the planet, π = pi
From the question, we were asked to find the value of g,
There we make g the subject of the equation
g = 4π²L/T²..................... Equation 2
Given: L= 48 cm = 0.48 m, T = (141/93) s = 1.516 s
Constant: π = 3.14
Substitute these values into equation 2
g = 4(3.14²)(0.48)/(1.516²)
g = 18.93/2.298
g = 8.24 m/s².
Hence the acceleration of the planet is 8.24 m/s²
A soccer player with a mass of 80.0 kg kicks a ball by applying a 20.0 N force. What force does the ball exert on the player?
A. 160. N
C. 2.50 N
B. 0.400 N
D. 20.0N
Answer:
F = 160.0 N
Explanation:
Given: Soccer payer with a mass = 80 kg, force = 20 N
To find: force
Formula: [tex]F=ma[/tex]
Solution: It is summarized by the equation: Force (N) = mass (kg) × acceleration (m/s²). Thus, an object of constant mass accelerates in proportion to the force applied.
F = m × a
F = 20 kg - 10 = 2
F = 80 × 2 = 160
F = 160.0 N
Newtons are derived units, equal to 1 kg-m/s². In other words, a single Newton is equal to the force needed to accelerate one kilogram one meter per second squared.
If the centripetal force is of the form m^a v^b r^c, find the values of a, b and c.
Answer with explanation:
What nuclear reaction is shown in the equation below?
Answer:
nuclear fission!!!
The nuclear fission is taken place in the given reaction.
What is nuclear fission and how it was related to the given equation?Nuclear fission reaction is the process how the larger energy particles hit by a neutron and separated into lighter elements with some energy. The lighter elements can exhibit energy in the form of electromagnetic radiation and in the form of kinetic energy.
For an example, the most known nucleus is Uranium - 235. This Uranium - 235 has the half life period of 740 million years. The Uranium - 235 when bombarded with neutrons, this causes the U-235 nucleus to split, producing, on average, Barium-141, Krypton-91, and three neutrons.
The given reaction is thus a nuclear fission reaction.
Thus, Option A is the correct answer.
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Calculate the speed of a gamma ray with a frequency of 3.0 x 10^19 Hz and a wavelength of 1.0 x 10^-11 m.
A.) 3.00 x 10^19 m/s
B.) 9.00 x 10^27 m/s
C.) 3.00 x 10^8 m/s
D.) 3.00 x 10^11 m/s
Answer:
Speed of gamma rays = 3 x 10⁸ m/s
Explanation:
Given:
Frequency of gamma ray = 3 x 10¹⁹ Hz
Wavelength of gamma rays = 1 x 10⁻¹¹ meter
Find:
Speed of gamma rays
Computation:
Velocity = Frequency x wavelength
Speed of gamma rays = Frequency of gamma ray x Wavelength of gamma rays
Speed of gamma rays = [3 x 10¹⁹][1 x 10⁻¹¹]
Speed of gamma rays = 3 x [10¹⁹⁻¹¹]
Speed of gamma rays = 3 x [10⁸]
Speed of gamma rays = 3 x 10⁸ m/s
A magnetic field points up through a loop where the area can be increased by dragging the side of the loop along the rails that make up 2 of the other sides. If you are looking down on the loop (magnetic field out of the page from your perspective) what is the direction of the induced current as the loop increases in area
Answer:
Explanation:
The magnetic field is pointing upwards , so magnetic flux is upwards . Due to increase in area , magnetic flux in upward direction will increase . Hence according to Lenz's law , induced current will be such that it will try to counter this increase . It is possible if current is in clockwise direction . Due to it magnetic field will be induced in downward direction thus reducing the total magnetic flux.
Hence direction of induced current will be clockwise direction in the loop as shown in the image enclosed .
Yellow-green light has a wavelength of 560 nm. What is its frequency?
Answer:
The frequency is 5.4 × 10^14Hz
Explanation:
The frequency of yellow-green light with a wavelength of 560 nm is approximately 5.4 x 10¹⁴ Hz.
What is the frequency of light?The frequency of yellow-green light with a wavelength of 560 nm can be calculated using the formula:
frequency = speed of light/wavelength
Where the speed of light is approximately 3.0 x 10⁸ meters per second.
First, we need to convert the wavelength from nanometers to meters by dividing by 10⁹:
560 nm = 560 x 10⁻⁹ m
Then, we can plug in the values and calculate the frequency:
frequency = (3.0 x 10⁸ m/s) / (560 x 10⁻⁹ m)
frequency ≈ 5.4 x 10¹⁴ Hz
Therefore, yellow-green light with a wavelength of 560 nm has a frequency of approximately 5.4 x 1014 Hz.
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What is the speed of a wave that has a frequency of 6 Hz and a wavelength of 4 m?
a) 24 m/s
b) 10 m/s
c) 30 m/s
d) 46 m/s
Answer:
a ) 24 m/s
Explanation:
Given,
Frequency ( f ) = 6 Hz
Wavelength ( λ ) = 4 m
To find : Speed ( v ) = ?
Formula : -
v = f x λ
v
= 4 x 6
= 24 m/s
Therefore, the speed of a wave that has a frequency of 6 Hz and a wavelength of 4 m
is 24 m/s.
20/05/2021
BP102T
- Which one of the following statements about reaction rate is false?
3253505030
Reaction rates are not sensitive to temperature.
Reaction rate is governed by the energy barrier between reactants and products.
Reaction rate is the speed at which the reaction proceeds.
Enzymes can accelerate the rate of a reaction.
Answer:
Reaction rate are not sensitive to temperature.
A 4500-kg helicopter accelerates upward at 2.0m/s2 what lift force is exerted by the air on the
helicopter?
Answer:
9000
Explanation:
f=ma
f= force
m=mass
a=acceleration
f=ma
4500×2.0
9000N
The proper time between two events is measured by clocks at rest in a reference frame in which the two events: The proper time between two events is measured by clocks at rest in a reference frame in which the two events:
a. are separated by the distance a light signal can travel during the time interval
b. occur at the same time
c. satisfy none of the above
d. occur in Nashville occur at the same coordinates
The proper time between two events is measured by clocks at rest in a reference frame in which the two events occur in Nashville occur at the same coordinates. So, option d.
What is meant by frame of reference ?The perspective from which you perceive and measure things is known as a reference frame. It's applied to describe how an object is moving or where it is.
Here,
Depending on the frame of reference, the time elapsed between two occurrences may vary, according to the Theory of Special Relativity.
The duration between two events occurring in the rest frame, as measured from a reference frame in motion relative to the rest frame, will always be longer than the correct time. Time dilation is a phenomenon that develops in accordance with the relativity of space and time.
A single clock that is present for both occurrences can be used to determine the right time difference between them.
The appropriate time between two events is the amount of time that elapses within a frame in which the two events take place at the same location, to put it another way.
Hence,
The proper time between two events is measured by clocks at rest in a reference frame in which the two events occur in Nashville occur at the same coordinates. So, option d.
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