P201 Exam III
An object of mass M oscillates on the end of a spring. To double the period, replace the object with one of mass:
4M
A styrofoam sphere of radius R has a density ρ. You now carefully compress the sphere so its radius is R/2. What is the density of the compressed sphere?
8 ρ
A mass on the end of a spring undergoes simple harmonic motion. At the instant when the mass is at its maximum displacement from equilibrium, what is its instantaneous acceleration?
At maximum displacement, its instantaneous acceleration is also at maximum.
A mass on the end of a spring undergoes simple harmonic motion. At the instant when the mass is at its maximum displacement from equilibrium, what is its instantaneous velocity?
At maximum displacement, its instantaneous velocity is zero.
bowling ball of mass 6.64kg and radius 9.80cm rolls without slipping down a lane at 5.06m/s. Calculate its total kinetic energy.
KE(tot)=KE(rot)+KE(trans) =119 J
A railroad tank car contains milk and rolls at a constant speed along a level track. The milk begins to leak out the bottom. The car then
Maintains constant speed
A small uniform disk and a small uniform sphere are released simultaneously at the top of a high inclined plane, and they roll down without slipping. Which one will reach the bottom first?
The sphere
Three containers are filled with water to the same height and have the same surface area at the base, but the total weight of water is different for each. (Figure 1) In which container does the water exert the greatest force on the bottom of the container?
all equal **#164
For vibrational motion, what term denotes the maximum displacement from the equilibrium position? wavelength amplitude frequency period
amplitude
A wooden block contains some nails so that its density is exactly equal to that of water. If it is placed in a tank of water and released from rest when it is completely submerged, it will
remain where it is released.
What is Bernoulli's equation when there is no flow (v1=v2=0)?
ΔP=ρgΔy
A metal bar is elongated by 2mm when put under a certain amount of tension. How much will it be elongated if the tension is doubled?
4 mm F = tension force = YA (\DeltaL/L ) \DeltaL is directly propotional to tension force F , hence when F is doubled , the value of \DeltaL become twice hence 4 mm
A cube of wood is floating on water. A cube of iron is totally submerged in water. The cubes are equal in volume. Which cube has the greater buoyant force acting on it?
The cube of iron has the greater buoyant force acting on it.
A wave transports -both energy and matter. . -matter but not energy. -energy but not matter.
energy but not matter
Which of the following statements are true? Check all that apply. A system that undergoes periodic motion never has a stable equilibrium position. Simple harmonic motion is periodic motion under the action of a restoring force that is directly proportional to the displacement from equilibrium. Simple harmonic motion is periodic motion under the action of a restoring force that is inversely proportional to the displacement from equilibrium. All periodic motions are simple harmonic motions. A system that undergoes periodic motion always has a stable equilibrium position.
-Simple harmonic motion is periodic motion under the action of a restoring force that is directly proportional to the displacement from equilibrium. -A system that undergoes periodic motion always has a stable equilibrium position.
A closed cubical chamber resting on the floor contains oil and a piston. If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp, which of the following statements is correct? (There could be more than one correct choice.) -The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber. -The pressure on the sides of the chamber will not increase. -The pressure everywhere in the oil will increase by Δp. -The pressure at the bottom of the oil will increase by more than Δp. -The pressure at the top of the oil will increase by less than Δp
-The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber. -The pressure everywhere in the oil will increase by Δp.
An object oscillates back and forth on the end of a spring. Which of the following statements are true at some time during the course of the motion? Check all that apply. -The object can have nonzero velocity and nonzero acceleration simultaneously. -The object can have zero velocity and, simultaneously, nonzero acceleration. -The object can have zero velocity and, simultaneously, zero acceleration. -The object can have zero acceleration and, simultaneously, nonzero velocity.
-The object can have nonzero velocity and nonzero acceleration simultaneously. ----> True everywhere except amplitudes/extremes and equilibrium -The object can have zero velocity and, simultaneously, nonzero acceleration. ---->True at extremes/amplitudes -The object can have zero acceleration and, simultaneously, nonzero velocity. ---->True at equilibrium
An object of mass m rests on a frictionless surface and is attached to a horizontal ideal spring with spring constant k. The system oscillates with amplitude A. The oscillation frequency of this system can be increased by -decreasing k. -decreasing m. -increasing A. -More than one of the above. -None of the above will work.
-decreasing m f= (1/2pi)sqrt(k/m)
When a baseball curves to the right (a curveball) , air is flowing -faster over the left side than over the right side. -faster over the right side than over the left side. -faster over the top than underneath. -at the same speed all around the baseball, but the ball curves as a result of the way the wind is blowing on the field.
-faster over the right side than over the left side Bernoulli's Principle Since the pressure on the left side of the ball is greater than the pressure on the right side, the air flow is faster over the right side than the right side.
Water flows in a horizontal pipe that is narrow but then widen and the speed of the water becomes less. The pressure in the water moving in the pipe is Check all that apply. -the same in both parts. -greater where the speed is higher -greater in the narrow part. -greater in the wide part. -greater where the speed is lower
-greater in the wide part -greater where the speed is lower
Two waves are traveling toward each other along a rope. When they meet, the waves -pass through each other. -bounce off of each other. -disappear.
-pass thru each other Principle of superposition says that when 2 waves travel thru the same point simultaneously, the resultant displacement of the particle is the sum of the displacement due to individual waves. This implies that even waves traveling towards each other can't disappear or bounce off of each other, but pass thru each other
A grandfather clock is "losing" time because its pendulum moves too slowly. Assume that the pendulum is a massive bob at the end of a string. Part A Part complete The motion of this pendulum can be sped up by: -decreasing the mass of the bob. -shortening the string. -increasing the mass of the bob. -lengthening the string.
-shortening the string T=(2pi)sqrt(L/g)
A disk, a hoop, and a solid sphere are released at the same time at the top of an inclined plane. They are all uniform and roll without slipping. In what order do they reach the bottom?
-sphere, disk, hoop hoop: I=mr^2 Disk: I=(1/2)mr^2 Sphere: I= (2/5)mr^2 The higher I, the more reluctant it is to roll down the hill
An object that can float in both water and in oil (whose density is less than that of water) experiences a buoyant force that is -the same when it is floating in water or in oil. -greater when it is floating in water than when floating in oil. -greater when it is floating in oil than when floating in water.
-the same when it is floating in water or in oil.
Suppose that we repeat the experiment shown in the video, but we replace one of the cylinders with a cylinder that has twice the radius (and use larger containers of water). If the height of the original cylinder is h, how deeply must we submerge the new cylinder to get the same weight reduction as in the video?
1/4h v of cylinder = 2pi(r^2)h
A bowling ball of mass 7.2 kg and radius 10 cm rolls without slipping down a lane at 2.6 m/s Calculate its total kinetic energy. in J
KE(total) = KE(t) + KE(r) = (mv² / 2) + (Iω² / 2) Moment of inertia, I, for a uniform solid sphere is: I = 2mr² / 5 ω = v / r =34J
The Young's modulus of aluminum is 69GPa, of nylon is 3GPa, of tungsten is 400GPa, and of copper is 117GPa. If equal-size samples were put under equivalent tensile stresses, how would you rank the materials by the degree to which they would be elongated?
Least to most elongation: Tungsten, copper, aluminum, nylon
Starting from rest, a solid sphere rolls without slipping down an incline plane. At the bottom of the incline, what does the angular velocity of the sphere depend upon?
The angular velocity depends upon the height of the incline. The angular velocity depends upon the radius of the sphere.
Why does an ocean liner float? Its very big size changes the way water supports it. It is held up in the water by large Styrofoam compartments. The average density of the ocean liner is less than that of seawater. It is made of steel, which floats. Remember the Titanic -ocean liners do not float
The average density of the ocean liner is less than that of seawater
A lump of putty and a rubber ball have equal mass. Both are thrown with equal speed against a wall. The putty sticks to the wall. The ball bounces back at nearly the same speed with which it hit the wall. Which object experiences the greater momentum change?
The ball experiences the greater momentum change.
A bowling ball hangs from a 1.0-m-long cord, (Figure 1): (i) A 200-gram putty ball moving 5.0 m/s hits the bowling ball and sticks to it, causing the bowling ball to swing up; (ii) 200-gram rubber ball moving 5.0 m/s hits the bowling ball and bounces straight back at nearly 5.0 m/s, causing the bowling ball to swing up. Describe what happens.
The ball swings up farther in (ii) than in (i).
In a lab environment, you are investigating the impulse of a force exerted on a brick when the brick's speed is reduced from 2.5 m/s to a complete stop. First, you allow the brick to slam into a secured piece of wood, bringing the brick to a sudden stop. Second, you allow the brick to plow into a large slab of gelatin so that the brick comes to a gradual halt. In which situation is there a greater impulse of the force on the brick?
The impulse is the same in both situations.
Which statement must be true for the momentum of a system to be conserved? The net external force on the system is non-zero. The net external force on the system is zero. The internal forces sum to zero. There are no external forces acting on the system.
The net external force on the system is zero.
Equal masses are suspended from two separate wires. The wires have identical lengths. The first wire has a larger cross-sectional area than the second wire. Which wire will stretch the LEAST?
The second wire will stretch the LEAST.
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct?
The small car and the truck experience the same average force. ---> according to newton's 3rd law, for every action there is an equal and opposite reaction
You are lying in bed and want to shut your bedroom door. You have a bouncy "superball" and a blob of clay, both with the same mass. Which one would be more effective to throw at your door to close it?
The superball.
A 10.0-N weight is suspended by two cords as shown in (Figure 1). What can you say about the tension in the two cords? (#113!!)
The tension in cord A is greater than that in cord B. Bigger angle = increased tension due to gravity
Beaker A is filled to the brim with water. Beaker B is the same size and contains a small block of wood which floats when the beaker is filled with water to the brim. Which beaker weighs more?
They are equal According to archimedes principle, the weight of water displaced is equal to the weight of the block
You hold a piece of wood in one hand and a piece of iron in the other. Both pieces have the same volume, and you hold them fully under water at the same depth. At the moment you let go of them, which one experiences the greater buoyancy force?
They experience the same buoyancy force.
A small car and a heavy pickup truck are both out of gas. The truck has twice the mass of the car. After you push both the car and the truck for the same distance with the same force, what can you say about the momentum and kinetic energy (KE) of the car and the truck? Ignore friction.
They have the same kinetic energy, but the truck has more momentum than the car.
A small car and a heavy pickup truck are both out of gas. The truck has twice the mass of the car. After you push both the car and the truck for the same amount of time with the same force, what can you say about the momentum and kinetic energy (KE) of the car and the truck? Ignore friction.
They have the same momentum, but the car has more kinetic energy than the truck.
What happens when two waves, such as waves on a lake, come from different directions and run into each other?
They may have various patterns where they overlap, but each wave continues with its original pattern away from the region of overlap.
A mass on the end of a spring undergoes simple harmonic motion. At the instant when the mass is at its equilibrium position, what is its instantaneous acceleration?
at equilibrium instantaneuous acceleration is 0 as force acting is zero
Two wave pulses pass each other on a string. The pulse traveling toward the right has positive amplitude, whereas the pulse traveling toward the left has equal amplitude in the negative direction. What happens when they occupy the same region of space at the same time?
destructive interference occurs
The boat in the water holds an iron anchor which is removed from the boat and placed on the shore. The level of the water will The boat in the water holds an iron anchor which is removed from the boat and placed on the shore. The level of the water will -fall. -rise. -stay the same.
fall **WHY
A rowboat floats in a swimming pool, and the level of the water at the edge of the pool is marked. Consider the following situations. The boat is removed from the water. The level of the water will
fall. ***WHY
If the sum of the external forces on an object is zero, then the sum of the external torques on it must also be zero.
false
A steel ball sinks in water but floats in a pool of mercury, which is much denser than water. Where is the buoyant force on the ball greater? A steel ball sinks in water but floats in a pool of mercury, which is much denser than water. Where is the buoyant force on the ball greater? submerged in the water floating on the mercury It is the same in both cases. It cannot be determined from the information given.
floating on the mercury
Two racecars are driving at constant speeds around a circular track. Both cars are the same distance away from the center of the track, but car 2 is driving twice as fast as car 1. The acceleration of car 2 is ___________ the acceleration of car 1.
four times The centripetal acceleration can be calculated by using ac=v2r. For a constant value of r, the centripetal acceleration will be proportional to the velocity squared. This results in a centripetal acceleration that is four times larger when the speed is doubled.
Constants A golf ball and an equal-mass bean bag are dropped from the same height and hit the ground. The bean bag stays on the ground while the golf ball rebounds. Which experiences the greater impulse from the ground?
golf ball
wo children are riding on a merry-go-round that is rotating with a constant angular speed. Abbie is one meter from the center of the merry-go-round, whereas Zak is two meters from the center. Abbie's acceleration is ___________ Zak's acceleration.
half of The centripetal acceleration can be calculated using ac=ω2r. The children have equal angular speeds, so their accelerations will depend directly on their distances from the center of the merry-go-round. Because Abbie's distance from the center is half as much as Zak's, her centripetal acceleration will be half of Zak's acceleration.
Bonnie sits on the outer rim of a merry-go-round, and Jill sits midway between the center and the rim. The merry-go-round makes one complete revolution every 2 seconds. Jill's linear velocity is:
half of Bonnie's. The time for a rotation is the same for both riders, but Bonnie, at the outer edge, travels in a larger circle than Jill. Bonnie therefore has a greater linear velocity.
The momentum of an isolated system is conserved
in both elastic and inelastic collisions
An air bubble underwater has the same pressure as that of the surrounding water. As the air bubble rises toward the surface (and its temperature remains constant), the volume of the air bubble
increases PV=RT
A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system
is half as much as before.
A woman is balancing on a high wire which is tightly strung, as shown in (Figure 1). The tension in the wire is
much more than the woman's weight
mass on a spring in SHM has amplitude A and period T. (Figure 1) At what point in the motion is the velocity zero and the acceleration zero simultaneously? At what point in the motion is the velocity zero and the acceleration zero simultaneously? x<0. x>0 but x<A. x=A x=0. None of the above.
none of the above
The space shuttle, in circular orbit around the Earth, collides with a small asteroid which ends up in the shuttle's storage bay. For this collision, a.) only momentum is conserved b.) only energy is conserved c.) momentum and energy are conserved d.) neither are conserved
only momentum is conserved.
For a wave, what term is defined as the time elapsed between two successive crests, or two successive troughs, passing by the same point in space? period wave velocity amplitude wavelength frequency
period
When you use the approximation sinθ≈θ for a pendulum, you must specify the angle θ in
radians ONLY
You put two ice cubes in a glass and fill the glass to the rim with water. As the ice melts, the water level -remains the same. -rises and water spills out of the glass. -drops at first, then rises until a little water spills out. -drops below the rim.
remains the same
A cylindrical rod has equal and opposite forces applied perpendicular to its circular ends. The forces are directed away from the rod, stretching the rod. What type of stress is this rod subject to?
tensile stress
When you blow some air above a paper strip, the paper rises. This happens because the air above the paper moves slower and the pressure is higher. the air above the paper moves slower and the pressure is lower. the air above the paper moves faster and the pressure remains constant. the air above the paper moves faster and the pressure is lower. the air above the paper moves faster and the pressure is higher.
the air above the paper moves faster and the pressure is lower.
A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change?
the ball
Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30° to the plane of the door. Which force exerts the greater torque about the door hinge?
the first force (applied perpendicular to the door) Perpendicular : Torque=Fr @30 degrees: Torque=(Fsin30)r
Two spheres have the same radius and equal mass. One sphere is solid, and the other is hollow and made of a denser material. Which one has the bigger moment of inertia about an axis through its center?
the hollow one
Suppose you pull a simple pendulum to one side by an angle of 5∘, let go, and measure the period of oscillation that ensues. Then you stop the oscillation, pull the pendulum to an angle of 10∘, and let go. The resulting oscillation will have a period about ________ the period of the first oscillation. one-fourth four times half the same as twice
the same as T does NOT depend on angle T=(2pi)sqrt(m/k)
During World War I, Germany used a "Big Bertha" cannon to hurl shells into Paris 30 miles away. This gun also had a very long barrel. What was the reason for using a long barrel in these guns?
to allow the force of the expanding gases from the gunpowder to act for a longer time
How is the smoke drawn up a chimney affected when a wind is blowing outside?
Smoke rises more rapidly in the chimney.
Consider the set of tubes shown in the figure. Each tube contains an unknown fluid that is less dense than the water it floats on top of. Rank the four unknown fluids from least dense to most dense.
**131
Consider a wave traveling down a cord and the transverse motion of a small piece of the cord. Which of the following is true? -The amplitude of the wave must be the same as the amplitude of a small piece of the cord. -The speed of the wave must be the same as the speed of a small piece of the cord. -The frequency of the wave must be the same as the frequency of a small piece of the cord. -All of the above are true. -Both the frequency and the amplitude of the wave must be the same as the frequency and the amplitude of a small piece of the cord.
-Both the frequency and the amplitude of the wave must be the same as the frequency and the amplitude of a small piece of the cord.
As water flows from a low elevation to a higher elevation through a pipe that changes in diameter, -the water pressure will decrease. -the water pressure will increase. -the water pressure will stay the same. -Need more information to determine how the water pressure changes.
-Need more information to determine how the water pressure changes.
When a rigid object rotates about a fixed axis, what is true about all the points in the object? (There could be more than one correct choice.) They all have the same radial acceleration. They all have the same angular acceleration. They all have the same tangential speed. They all have the same tangential acceleration. They all have the same angular speed.
-They all have the same angular acceleration -They all have the same angular speed
Two speakers face each other, and they each emit a sound of wavelength λ. One speaker is 180∘ out of phase with respect to the other. If we separate the speakers by a distance 1.5λ, how far from the left-most speaker should we place a microphone in order to pick up the loudest sound? Ignore reflections from nearby surfaces. Select all that apply.
0 lamda, 1/2lamda, 1 lamda
A diver can reduce her moment of inertia by a factor of 3.5 when changing from a straight position to the tuck position. If she makes 2.0 rotations in 1.5 seconds when in the tuck position, what is her angular speed when in the straight position?
2/1.5 = 1.333 rev/s 1.333 / 3.5 = 0.38 rev/s
Which of the following are true? A) the total momentum of an isolated system is constant B) the total momentum of any number of particles is equal to the algebraic sum of the momenta of individual particles. C) the total momentum of any number of particles is equal to the vector sum of the momenta of individual particles D)The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time E)The total momentum of any system is constant F)The vector sum of forces acting on a particle equals the rate of change of velocity of the particle with respect to time
A) the total momentum of an isolated system is constant C) the total momentum of any number of particles is equal to the vector sum of the momenta of individual particles D)The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time
You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You have two choices about what to do with the ball: either catch the ball or deflect it back toward your friend with the same speed as it was originally thrown. Which choice should you make in order to maximize your speed on the skateboard?
Deflect the ball back.
A heavy ball suspended by a cable is pulled to the side by a horizontal force F⃗ as shown in (Figure 1). If angle θ is small, the magnitude of the force F can be less than the weight of the ball because:
F⃗ is equal to only the x component of the tension in the cable.
A parking garage is designed for two levels of cars. To make more money, the owner decides to double the size of the garage in each dimension (length, width, and number of levels). For the support columns to hold up four floors instead of two, how should he change the columns' diameter?
Increase the area of the columns by a factor of 8 by increasing their diameter by a factor of 2√2
A student attaches one end of a Slinky to the top of a table. She holds the other end in her hand, stretches it to a length ℓ, and then moves it back and forth to send a wave down the Slinky. If she next moves her hand faster while keeping the length of the Slinky the same, how does the wavelength down the Slinky change? It increases. It decreases. It stays the same.
It decreases See equations in notebook. wavelength is inversely related to frequency
A small mass m on a string is rotating without friction in a circle. The string is shortened by pulling it through the axis of rotation without any external torque (Figure 1). What happens to the angular velocity of the object?
It increases. Without an external torque students may think that the angular speed would remain constant. But with no external torque, the angular momentum must remain constant. The angular momentum is the product of the moment of inertia and the angular speed. As the string is shortened, the moment of inertia of the block decreases. Thus, the angular speed increases.
Two identical billiard balls traveling at the same speed have a head-on collision and rebound. If the balls had twice the mass, but maintained the same size and speed, how would the rebound be different?
No difference.
Hot air is less dense than cold air. Could a hot-air balloon be flown on the Moon, where there is no atmosphere? -Yes, warm air always rises, especially in a weak-gravitational field like that of the Moon. -No, there is no cold air to displace, so no buoyancy force would exist. -Yes, but the balloon would have to be filled with helium instead of hot air.
No, there is no cold air to displace, so no buoyancy force would exist.
What is the power needed to drive a fluid through a pipe with uniform cross-section? Ignore viscosity. Take that Q is the volume rate of flow and ΔP is the pressure difference.
Power=ΔPQ
Ultimate strength point on graph, proportional limit, elastic limit, breaking poin
Question #118, 119,120,121!!
Suppose you are sitting on a rotating stool holding a 2-kg mass in each outstretched hand. If you suddenly drop the masses, your angular velocity will
Stay the same Students may mistakenly reason that since no net torque acts on you and your moment of inertia decreases as the masses are released, your angular speed should increase. This reasoning is erroneous because the angular momentum of the system of you and the masses is conserved. As the masses fall they carry angular momentum with them. If you consider you and the masses as two separate systems, each with angular momentum from their moments of inertia and angular speed, it is easy to see that by dropping the masses, no net external torque acts on you and your moment of inertia does not change, so your angular speed will not change. The angular momentum of the masses also does not change until they hit the ground and friction (external torque) stops their motion
Which of the following increases the speed of waves in a stretched elastic cord? (More than one answer may apply.)
Stretching the elastic cord further.
As you increase the force that you apply while pulling on a rope, which of the following is NOT affected? The Young's modulus of the rope. The strain on the rope. The stress on the rope. All of the above. None of the above.
The Young's modulus of the rope --> this is a constant based on the material
Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?
The force would be the same in both cases.
A girl and a boy are riding on a merry-go-round that is turning at a constant rate. The girl is near the outer edge, and the boy is closer to the center. Who has greater linear speed?
The girl has the greater linear speed
A small solid sphere and a small thin hoop are rolling along a horizontal surface with the same translational speed when they encounter a 20 ∘ rising slope. If these two objects roll up the slope without slipping, which will rise farther up the slope?
The hoop If you do not take into account the energy of rotation, you would answer that the two objects would rise to the same height. Another common misconception is that the mass and/or diameter of the objects will affect how high they travel. When using conservation of energy to relate the total initial kinetic energy (translational and rotational) to the final potential energy, the mass and radius of the objects cancel out. The thin hoop has a larger moment of inertia (for a given mass and radius) than the solid sphere. It will therefore have a greater total initial kinetic energy, and will travel to a greater height on the ramp. Provide Feedback
What represents the impulse of the force in a graph of force versus time?
The impulse is equal to the area under the curve.
The maximum stress a bone can experience before it fractures is around 108N/m2. How much stress could the bone experience if it were twice as large in diameter?
The maximum stress would be no different.
A gas-filled balloon is submerged in a fluid. As a result, the balloon is subject to inward forces from all sides. How does the volume of the balloon change?
The volume of the object decreases.
A piece of wood is floating in a tub of water. A second piece of wood rests on top of the first piece; it does NOT touch the water. If the second piece of wood is removed from on top of the first piece and placed in the water, what happens to the water level in the tub? A
The water level remains unchanged.
Two wheels having the same radius and mass rotate at the same angular velocity ((Figure 1)). One wheel is made with spokes so nearly all the mass is at the rim. The other is a solid disk. How do their rotational kinetic energies compare?
The wheel with spokes has about twice the KE.
Two wheels having the same radius and mass rotate at the same angular velocity ((Figure 1)). One wheel is made with spokes so nearly all the mass is at the rim. The other is a solid disk. How do their rotational kinetic energies compare?
The wheel with spokes has about twice the KE.
Three cars, car X, car Y, and car Z, begin accelerating from rest at the same time. Car X is more massive than car Y, which is more massive than car Z. The net accelerating force exerted on each car is identical. After 10 seconds, which car has the most amount of momentum?
They all have the same amount of momentum.
Consider a solid uniform sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational?
Translational kinetic energy is larger.