ch 8 physics

A 0.060-kg tennis ball, initially moving at a speed of 12 m/s, is struck by a racket causing it to rebound in the opposite direction at a speed of 18 m/s. What is the change in momentum of the ball?

-1.8 kg* m/s

A-70 kg astronaut is making repairs outside a space capsule and is motionless when his tether line breaks. In order to return to the capsule, he throws his 2.0-kg space wrench at a speed of 14 m/s in a direction directly away from the capsule. At what speed does the astronaut move toward the capsule?

0.40 m/s

A 5-kg fish swimming at a velocity of 1 m/s swallows an absent-minded 1-kg fish at rest. What is the speed of the larger fish after lunch?

0.83 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

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

3 m/s

A 10 N force acts on a 5.0 kg mass, initially at rest, for 2.5 s. What is the final speed of the mass?

5 m/s

A mass on an air track is traveling with a speed of 10 m/s when it collides inelastically with an identical second mass initially at rest. What is the speed of the two mass system after the collision?

5 m/s

A 10 N force acts on a 2.0 kg object for 5.0 s. What is the object's change in momentum?

50 kg * m/s

A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car?

6 m/s

Momentum is transferred to the ground when an apple falls on it. The momentum absorbed by the ground is . . .

Greater than that of the apple only if the apple bounces

Which of the following would have the greatest momentum?

a car speeding along a highway

You're driving down the highway and a bug hits your windshield. Which undergoes the greater change in momentum?

both are the same

Which would produce a greater change in momentum, driving into a very massive concrete wall with no "give," or having a head-on collision at the same speed with an identical car moving toward you with the same speed?

both the same

It is correct to say that impulse is equal to . . . *

change in momentum

A train rolls along a track with great momentum. If it rolls at the same speed but has twice as much mass, its momentum is . . .

doubled

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

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

increased time of impact

Which of the following is a unit of measurement of momentum?

kg* m/s

When you are in the way of a fast moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a . . .

long time

A moving object on which no forces are acting will continue to move with constant . . .

momentum

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

more mass, more momentum, less stopping distance

A cannon recoils from firing a cannonball. The speed of the cannon's recoil is small because . . .

the cannon has more mass than the cannonball