ch 6

which of the following has the largest momentum relative to the earth's surface?

a pickup truck speeding along a highway

when you jump from an elevated position you usually bend your knees upon reaching the ground. by doing this, you make the time of impact about 10 times as great for a stiff legged landing. in this way the average force your body experiences is

about 1/10 as great

is all people, animals, trains, and trucks all over the world began to walk or run toward the east, then

earth would spin a bit slower

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

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

identical to the force applied to the cement block

padded dashboards in cars are safer in an accident than non padded ones b/c an occupant hitting the dash has

increased time of impact

it is correct to say that impulse is equal to

momentum

a large metal ball is shot from a cannon w a short barrel. if the same ball were to be shot from cannon w a longer barrel, its muzzle velocity would be

more

a car traveling along the highwayneeds 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 mass, more momentum, and less stopping distance

a golf ball moving forward w 1 unit of memoentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. the bowling ball is set in motion w a momentum of

more than one unit

an astronout, floating alone in outer space, throws a baseball. if the ball floats away at a speed of 20 m/s, the astronaut will

move in the opposite direction, but a a lower speed

the conservation of momentum is most likely related to

newtons 3rd law

compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor b/c the

stopping time is longer on te carpet

suppose that a tiny gun made of a strong but very light material fires a bullet that is more massive than the gun itself. for such weaoin

the target would be safer than the shooter

two billard balls having the same mass and speed roll towards each other. what is their comines momentum after they meet?

0

a 1 kg glider and a 2 kg glider both slide toward each other at 1m/s on an air track. they collide and stivk. the combined mass moves at

1/3 m/s

a ball is moving at 3m/s and has a momentum of 48kgm/s. what is the balls mass?

16 kg

a 1 kg chunk of putty moving at 1m/s collides w and sticks to a 5 kg bowling ball initially at rest. the bowling ball and putty then move w a momentum of

1kg m/s

a riffle mass of 2 kg is suspended by stings. the rifle fires a bullet of mass 0.01 kg at a speed of 200 m/s. the recoil velocity of the rifle is about

1m/s

a 1000 kg car moving at 10 m/s brakes to stop in 5 s. the avg braking force is

2000 N

a 1000 kg car moving at 10 m/s brakes to stop in 5 s. the avg breaking force is

2000 N

a 5000 kg freight car runs into a 10000 kg freight car at rest. they couple upon collision and move w a speed of 2m/s. what was the initial speed of the 5000 kg car?

6 m/s