Physics Chapter 6

bouncing

The greater efficiency achieved with the curved blades of a Pelton wheel is due to

Newton's 2nd law

The impulse-momentum relationship is a direct result of

16 kg

The mass of a ball moving at 3 m/s with a momentum of 48 kg m/s is

3 m/s

The speed of a 4-kg ball with a momentum of 12 kg m/s is

flying in different directions

The total momentum of a flock of identical birds could be zero only if the birds are

1 kg m/s

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

1/3 m/s

A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

1 m/s

A 2-kg rifle that is suspended by strings fires a 0.01-kg bullet at 200 m/s. The recoil velocity of the rifle is about

5/6 m/s

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

1/6 m/s

A 5-kg shark swimming at 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the shark after his meal is

6 m/s

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

2 m/s

A 5000-kg freight car moving at 2 m/s collides with a 10,000-kg freight car at rest. They couple upon collision and move away at

1.5 g.

A bungee jumper attains a speed of 30 m/s just as the bungee cord begins to stretch. If the period of stretch is 2 s while coming to a halt, the jumper's average deceleration is about

cannon has much more mass than the cannonball

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

continue along the path as if the explosion didn't occur

A cannonball following a parabolic path explodes into fragments. The momentum of the fragments

all of the above

A car traveling along the highway brakes to a stop over a certain distance. More braking force is required if the car has

need more information

A falling 1-N apple hits the ground with a force of about

moves in the direction of the wind impact force

A fan attached to an ice sail craft stalled on a windless day blows air into the sail that bounces backward upon impact. The boat

equals the momentum of the firecracker at the time of burst

A firecracker bursts while freely falling. The combined momentum of its fragments

twice

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

more than 1 unit

A golf ball moving forward with 1 unit of momentum 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 with a momentum of

greater

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 with the force that stops the car, the force needed to stop the truck is

bounces upon impact

A karate chop is more effective if one's hand

less momentum

A large heavy truck and a small baby carriage roll down hill. Neglecting friction, at the bottom of the hill, the baby carriage will likely have

3,000 kg m/s

A motorcycle of mass 100 kilograms slowly rolls off the edge of a cliff and falls for three seconds before reaching the bottom of a gully. Its momentum upon hitting the ground is

1 unit

A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. Both move with a combined momentum of.

momentum

A same-size iron ball and wooden ball are dropped simultaneously from a tower and reach the ground at the same time. The iron ball has a greater

none of the above

A sandbag motionless in outer space is hit by a three-times-as massive sandbag moving at 12 m/s. They stick together and move at a speed of

in an extended time

A softer landing occurs when a falling object bounces from a surface

the target would be safer than the shooter

A tiny gun made of a strong but very light material fires a bullet more massive than the gun itself. For such a weapon

move in the opposite direction at a lower speed

An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will

decreases

An open freight car rolls friction free along a horizontal track in a pouring rain that falls vertically. As water accumulates in the car, the car's speed

all of the above

As Bronco Brown steps off a hovering, high-flying helicopter and falls through the air, he experiences

Stopping time is longer on the carpet

Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

move away from each other, but at different speeds

If a monkey floating in outer space throws his hat away, the hat and the monkey will both

Earth would spin a bit slower

If all people, animals, trains and trucks all over the world began to walk or run towards the east (opposite the direction of Earth's spin), then

acceleration

If several balls are thrown straight up with different initial speeds, the quantity that will have the same value along their paths is their

lengthened time of contact

Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter

zero

Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be

2000N

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

6 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

Newton's 3rd law

The conservation of momentum is most clearly related to

all of the above

The force on a dropped apple hitting the ground depends upon

exhaust gases

The force that accelerates a rocket in outer space is exerted on the rocket by the

zero

Two billiard balls having the same mass and speed roll towards each other. What is their combined momentum after they meet?

the faster car

Two identical freight 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 together, and roll away in the direction of

1/2 m/s

Two identical gliders slide toward each other on an air track. One moves at 1 m/s and the other at 2 m/s. They collide, stick, and moves at

Both the same

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is

greater with the brick wall

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is

Either of these depending on speed

Which has the greater momentum when moving?

a pickup truck speeding along a highway

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

time of contact is increased

To catch a fast-moving ball, you extend your hand forward before contact with the ball and let it ride backward in the direction of the ball's motion. Doing this reduces the force of contact on your hand principally because the

5000 kg 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

0.5 m/s

Two identical objects in outer space, one moving at 2 m/s, the other at 1 m/s, have a head-on collision and stick together. Their combined speed after the collision is

at 45 degrees to the direction of either car before collision

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

greater than the magnitude of momentum of either car before collision

Two vehicles with equal magnitudes of momentum traveling at right right angles to each other undergo an inelastic collision. The magnitude of momentum for the combined wreck is

decreases

When Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard, the speed of the skateboard

neither of these

When Peter tosses an egg against a sagging sheet, the egg doesn't break due to

the time of contact is increased

When a boxer is moving away from a punch, the net force experienced is reduced because

increased

When a boxer moves into an oncoming punch, the force experienced is

both of these

When a vertically falling firecracker bursts, the vector sum of momentum fragments

decreased

When bullets are fired from an airplane in the forward direction, the momentum of the airplane is

about 1/10 as great

When you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing. In this way the average force your body experiences is

both the same

Which produces more force: driving into a very massive concrete wall with no "give," or having a head-on collision with an identical car moving toward you at the same speed?

both the same

You're driving down the highway and a bug splatters into your windshield. Which undergoes the greater change in momentum during the time of contact.