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
