Physics Momentum and Impulse

-2.5 m/s -

A 10,000.0 kg trolley moving at 4.0 m/s collides and couples with a 6000.0 kg trolley which is initially at rest. The final speed of the trolleys is:

30 kgm/s

A 3 kg ball is dropped onto a concrete floor. What is the magnitude of the ball's change in momentum if its speed just before striking the floor is 7 m/s and its rebound speed is 3 m/s?

1.5 m/s

A 3.0 kg toy truck moves freely along a track at 2.0 m/s and collides with a 1.0 kg toy car that is at rest. After the collision, the two cars stick together. What is their velocity after the collision?

-.06 m/s in the opposite direction of the box

A 40.0 kg physics student at rest on a frictionless rink throws a 3.0 kg box, giving the box a velocity of 8.0 m/s. Which statement describes the initial velocity of the student after the box is thrown?

5 m/s

A 6 kg block moves with a constant speed 5 m/s on a horizontal frictionless surface and collides elastically with an identical block initially at rest. The second block collides and sticks to the last 6 kg block which was initially at rest. What is the speed of the second 6 kg block after the first collision?

2.5 m/s

A 6 kg block moves with a constant speed 5 m/s on a horizontal frictionless surface and collides elastically with an identical block initially at rest. The second block collides and sticks to the last 6 kg block which was initially at rest. What is the speed of the third 6 kg block after the second collision?

Same time for both

A bowling ball and a ping-pong ball are rolling toward you with the same momentum. If you exert the same force to stop each one, which takes a longer time to bring to rest?

Ping-pong ball

A bowling ball and a ping-pong ball are rolling toward you with the same momentum. If you exert the same force to stop each one, for which is the stopping distance greater?

Nearly 2v

A bowling ball moving with speed, v collides head-on with a stationary tennis ball. The collision is elastic, and there is no friction. The bowling ball barely slows down. What is the speed of the tennis ball after the collision?

5 m/s

A box slides with initial velocity 10 m/s on a frictionless surface and collides inelastically with an identical box. The boxes stick together after the collision. What is the final velocity?

.5 m/s to the right

A cannon sits on a stationary railroad flatcar with a total mass of 1000 kg. When a 10-kg cannon ball is fired to the left at a speed of 50 m/s, what is the recoil speed of the flatcar?

p^2/2m

A car of mass m is moving with a momentum p. How would you represent its kinetic energy in terms of these two quantities?

The carpenter and the hammer will have equal and opposite momentum

A carpenter is initially at rest on an icy pond when he decides to throw his hammer. After being thrown, the hammer moves in one direction while the carpenter moves off in the opposite direction. Which of the following correctly describes this activity?

-100 N -

A hockey stick strikes a 0.50 kg puck and is in contact with the puck for t = 0.050 s. The puck travels in a straight line as it approaches and leaves the hockey stick after it is struck. The puck arrives at the stick with a velocity of 6.4 m/s and leaves with a velocity of -3.6 m/s. What is the magnitude of the average force acting on the puck?

5 kgm/s

A hockey stick strikes a 0.50 kg puck and is in contact with the puck for t = 0.050 s. The puck travels in a straight line as it approaches and leaves the hockey stick after it is struck. The puck arrives at the stick with a velocity of 6.4 m/s and leaves with a velocity of -3.6 m/s. What is the magnitude of the change in momentum of the puck?

Equal to

A net force of 200 N acts on a 100-kg boulder, and a force of the same magnitude acts on a 130-g pebble. How does the rate of change of the boulder's momentum compare to the rate of change of the pebble's momentum?

Less than

A net force of 200 N acts on a 100-kg boulder, and a force of the same magnitude acts on a 130-g pebble. How does the rate of change of the boulder's velocity compare to the rate of change of the pebble's velocity?

Hailing

A person stands under an umbrella during a rainstorm. Later the rain turns to hail, although the number of "drops" hitting the umbrella per time and their speed remains the same. Which case requires more force to hold the umbrella?

-5kgm/s -I=p=m(delta)v

A rubber ball with a mass of 0.25 kg and a speed of 9.0 m/s collides perpendicularly with a wall and bounces off with a speed of 11 m/s in the opposite direction. What is the magnitude of the impulse acting on the rubber ball?

The rubber ball

A small beanbag and a bouncy rubber ball are dropped from the same height above the floor. They both have the same mass. Which one will impart the greater impulse to the floor when it hits?

Both have the same momentum change

A small car and a large truck collide head-on and stick together. Which one has the larger momentum change?

The net final momentum of the two objects is 0

A spring is compressed between two blocks with unequal masses, m1 and m2, held together by a spring as shown above. The objects are initially at rest on a horizontal surface with no friction. The spring is then cut. What is true of the two object system after the spring is cut?

Arrow pointing down

A stationary cannon ball explodes in three pieces of masses m, m and 2m. The momentum of the equal masses (m1 and m2) is shown in the diagram below. (m1 going northwest and m2 going northeast) What is the direction of the momentum of the 2m mass?

((√2)/2)v

A stationary cannon ball explodes in three pieces of masses m, m and 2m. The momentum of the equal masses (m1 and m2) is shown in the diagram below. What is the magnitude of the velocity of the 2m cannon ball piece?

Arrow pointing southeast

A steel ball (1) moving at a constant speed, v on a horizontal frictionless surface, collides obliquely with an identical ball (2) initially at rest. The velocity of the first ball before and after the collision is shown on the diagram . What is the approximate direction of the velocity of the second ball after the collision? (1 heading to the right toward the ball then going off northeast)

-4 s -I=Ft=p -240=60t

How long must a 60 N net force act to produce a change in momentum of 240 kg m/s?

All 3

If all three collisions below are totally inelastic, which one(s) will bring the car on the left to a complete halt? (one car hits a brick wall, another hits a car with mass 2m moving at half its velocity, and another hits a car with mas .5m moving at 2v)

The third one

If all three collisions below are totally inelastic, which one(s) will cause the most damage (in terms of lost energy)? (one car hits a brick wall, another hits a car with mass 2m moving at half its velocity, and another hits a car with mas .5m moving at 2v)

The momentum of the system is zero

A system of particles is known to have a total kinetic energy of zero. What can you say about the total momentum of the system?

No

A system of particles is known to have a total momentum of zero. Does it necessarily follow that the total kinetic energy of the system is also zero?

Decreases

A truck moves along a frictionless level road at a constant speed. The truck is open on top. A large load of gravel is suddenly dumped into the truck. The velocity of the truck:

Same for both

A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater momentum?

The light one

A uranium nucleus (at rest) undergoes fission and splits into two fragments, one heavy and the other light. Which fragment has the greater speed?

3v

Carefully place a small rubber ball (mass m) on top of a much bigger basketball (mass M) and drop these from some height h. What is the velocity of the smaller ball after the basketball hits the ground, reverses direction, and then collides with small rubber ball?

18 m/s

Amy (150 lbs) and Gwen (50 lbs) are standing on slippery ice and push off each other. If Amy slides at 6 m/s, what speed does Gwen have?

-20N/s -

An object of mass 3.0 kg starts from rest and moves along the x-axis. A net horizontal force is applied to the object in the +x direction. The Force-time graph is shown below. What is the net impulse delivered by the applied force? (from F=6 to F=0 in 2 s)

-150 J -

An object of mass 3.0 kg starts from rest and moves along the x-axis. A net horizontal force is applied to the object in the +x direction. The Force-time graph is shown below. What is the net work done on the object by the applied force? (from F=6 to F=0 in 2 s)

-2.0 m/s -

An object with a mass of 2.0 kg is accelerated from rest. The above graph shows the magnitude of the net force as a function of time. At t = 4.0 s and F= 2 N the object's velocity is closest to...

One arrow pointing northeast and the other pointing southeast

An object with an initial momentum moving from left to right collides with another object at rest. Which of the following combinations of two vectors may represent the momentum of the two objects after the collision?

Slows down

An open cart rolls along a frictionless track while it is raining. As it rolls, what happens to the speed of the cart as the rain collects in it? (assume that the rain falls vertically into the box).

2mvcosø

As shown below, a tennis ball of mass, m rebounds from a vertical wall with the same speed v as it had initially. What is the change in momentum of the ball? (m heading northeast, then hits wall and begins heading northwest)

Situation 2

Consider two elastic collisions: 1) a golf ball with speed v hits a stationary bowling ball head-on. 2) a bowling ball with speed v hits a stationary golf ball head-on. In which case does the golf ball have the greater speed after the collision?

The lighter one

If two boxes, one heavier than the other, are initailly at rest on a horizontal frictionless surface and a constant force acts on them for the same period of time, which box has the larger velocity after the force acts?

9.1 m/s

Object A with a mass of 8.0 kg travels to the east at 10.0 m/s and object B with a of mass 3.0 kg travels south at 20.0 m/s. The two objects collide and stick together. What is the magnitude of the object's combined velocity after the collision?

37 degrees south of east

Object A with a mass of 8.0 kg travels to the east at 10.0 m/s and object B with a of mass 3.0 kg travels south at 20.0 m/s. The two objects collide and stick together. What is the direction of the velocity after the collision?

KEf=KEi/2

On a frictionless surface, a sliding box collides and sticks to a second identical box which is initially at rest. What is the final KE of the system in terms of the initial KE?

0

Two blocks are on a frictionless surface and have the same mass m. Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides elastically with block 2. What is the final speed of block 1?

4v

Two blocks are on a frictionless surface and have the same mass m. Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides elastically with block 2. What is the final speed of block 2?

2v

Two blocks are on a frictionless surface and have the same mass m. Block 2 is initially at rest. Block 1 moves to the left with speed 4v and collides inelastically with block 2. Which of the following choices is closest to the final speed of the system of two blocks?

Both the same

Two boxes, one heavier than the other, are initially at rest on a horizontal frictionless surface. The same constant force F acts on each one for exactly 1 second. Which box has more momentum after the force acts?

1 m/s

Two friends with mass 60.0 kg and 40.0 kg run directly toward each other with speeds 3.0 m/s and 2.0 m/s respectively. If they hold on to each other after they collide, their combined speed just after the collision will be:

No (depends on the velocity, in KE, velocity is squared)

Two objects are known to have the same momentum. Do these two objects necessarily have the same kinetic energy?

It has more kinetic energy than the gun

When a bullet is fired from a gun, the bullet and the gun have equal and opposite momenta. If this is true, then why is the bullet deadly? (whereas it is safe to hold the gun while it is fired).

3.0 m/s

When a ping-pong ball rolling with a speed of 3.0 m/s collides with a bowling ball at rest, the ping-pong's speed after the collision will be close to:

Momentum

When the velocity of a moving object is quadrupled, which of the following is also quadrupled: kinetic energy, momentum, potential energy, or acceleration?

Momentum is conserved during the collision

Which of the following is true about an object of mass, m1 moving on a horizontal frictionless surface that strikes and sticks to an object of mass m2 (m1>m2)?

Superball

You are lying in bed and you want to shut your bedroom door. You have a superball and a blob of clay (both with the same mass) sitting next to you. Which one would be more effective to throw at your door to close it?

Makes no difference

You drive around a curve in a narrow one-way street at 30 mph when you see an identical car heading straight toward you at 30 mph. You have two options: hit the car head-on or swerve into a massive concrete wall (also head-on). What should you do?

Greater than

You tee up a golf ball and drive it down the fairway. Assume that the collision of the golf club and ball is elastic. When the ball leaves the tee, how does its speed compare to the speed of the golf club?