Impulse/Momentum

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

16 kg

A 5000-kg freight car moving at 2 m/s runs into a 10,000-kg freight car at rest. They couple upon collision and move away as one body at

2/3 m/s

A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is

2000 N

What is the magnitude of the impulse on an 9.0-kg ball rolling at 2.6 m/s when it bumps into a pillow and stops?

23 N⋅s

A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?

3 m/s

Two 5000-kg rail cars roll without friction (one at 1 m/s, the other at 2 m/s) toward each other on a level track. They collide, couple, and roll together with a combined momentum of

5000 kg m/s

The change in momentum that occurs when a 1.0 kg ball traveling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is

6 kg m/s

Joanne drives her car with a mass of 1000 kg at a speed of 23 m/s. Find a road friction force that is need to bring her car to a halt in 6.0 s.

F = 3800 N

How much impulse stops a 40-kg carton sliding at 3.2 m/s when it meets a rough surface? Impulse = change in momentum: Ft=Δmv

J = 130 N⋅s

Which of the following has the largest momentum relative to the Earth's surface?

a pickup truck speeding along a highway

Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The combined wreck moves in a direction

at 45 degrees to the direction of either car before collision

A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is

greater

Cassy can get more force on the bricks she breaks with a blow of her bare hand when _______.

her hand is made to bounce from the bricks

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is

identical to the force applied to the block

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has

increased time of impact

A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has

more momentum, more mass and less stopping distance

An astronaut , floating alone in outer space, throws a baseball. If the ball floats away at a speed of 20 meters per second, the astronaut will

move in the opposite direction, but at a lower speed

It is correct to say that impulse is equal to

the change in momentum it produces.

A 2.60-kg blob of putty moving at 4.00 m/s slams into a 4.60-g blob of putty at rest. Calculate the speed of the two stuck-together blobs of putty immediately after colliding. Conservation of momentum: mvbefore=mvafter

v = 3.99 ms

When a falling firecracker explodes, the momenta of its pieces _______.

vectorally add to equal the initial momentum of the firecracker