1025 Physics Chapter 6

The greater efficiency achieved with cured blades of a Pelton wheel is due to... a.) greater time of water impact b.) bouncing c.) divided impulse d.) rational momentum

b.) bouncing

It is correct to say that impulse is equal to... a.) momentum b.) corresponding change in momentum c.) force * the distance it acts upon d.) velocity * time

b.) corresponding change in momentum

The impulse-momentum relationship is a direct result of... a.) newton's second law b.) newton's third law c.) newton's law of gravity d.) newton's 1st law

a.) newton's second law

A 5 kg shark swimming at 1 m/s swallows an absent-minded 1 kg fish swimming towards it at 4 m/s. The speed of the shark after his meal is... a.) 1/2 m/s b.) 1/5 m/s c.) 1/6 m/s d.) 2/3 m/s e.) 3/2 m/s

c.) 1/6 m/s

The mass of a ball moving at 3 m/s with a momentum of 48 kg m/s is... a.) 4 kg b.) 12 kg c.) 16 kg d.) 144 kg e.) none

c.) 16 kg

A motorcycle of mass 100 -kg slowly rolls off of the edge of a cliff and falls for 3 seconds before reaching the bottom of a gully. Its momentum upon hitting the ground is... a.) 1000 kg m/s b.) 2000 kg m/s c.) 3000 kg m/s d.) 4000 kg m/s e.) 9000 kg m/s

c.) 3000 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... a.) 10,000 kg m/s b.) 15,000 kg m/s c.) zero d.) 5000 kg m/s

d.) 5000 kg m/s

When Peter tosses an egg against a sagging sheet, the egg doesn't break due to... a.) reduced impulse b.) reduced momentum c.) both d.) neither

d.) neither

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.. a.) 0.5 m/s b.) 0.33 m/s c.) 1.0 m/s d.) 0.67 m/s e.) none

a.) 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... a.) 0.5 m/s b.) 0.33 m/s c.) 0.67 m/s d.) 1.0 m/s e.) none

a.) 0.5 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... a.) 1/3 m/s b.) 1/2 m/s c.) 1/6 m/s d.) 0 m/s e.) 1.5 m/s

a.) 1/3 m/s

Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick upon collision, their speed after collision will be... a.) 1/6 m/s b.) 1/4 m/s c.) 1 m/s d.) 1/5 m/s e.) none

a.) 1/6 m/s

The speed of a 5-kg ball with a momentum of 12 kg m/s is... a.) 3 m/s b.) 4 m/s c.) 12 m/s d.) 48 m/s e.) none

a.) 3 m/s

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... a.) at 45 degrees to the direction of either car before collision b.) parallel to either c.) at some angle other than 45 degrees

a.) at 45 degrees to the direction of either car before collision

When Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard, the speed of the skateboard... a.) decreases b.) increases c.) neither decreases nor increases

a.) decreases

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

a.) greater

Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter... a.) lengthened time of contact b.) shorter time of contact c.) decreased impulse d.) increased momentum

a.) lengthened time of contact

Compared with falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the... a.) stopping time is longer on the carpet b.) stopping time is shorter on the carper c.) carpeted floor provides a smaller impulse d.) carpet provides a smaller impulse and longer time

a.) stopping time is longer on the carpet

A 1 kg chunk of putty moving at 1 m/s collides with and sticks to a 5 kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of... a.) 0 kg m/s b.) 1 kg m/s c.) 2 kg m/s d.) 5 kg m/s e.) more than 5 kg m/s

b.) 1 kg m/s

A 2 kg rifle that is suspended by a string fires a 0.01 kg bullet at 200 m/s. the recoil velocity of the rifle is about... a.) 0.1 m/s b.) 1 m/s c.) 0.01 m/s d.) 0.001 m/s e.) none

b.) 1 m/s

The average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5s is... a.) 1000N b.) 2000N c.) 3000N d.) 4000N e.) 5000N

b.) 2000N

Which of the following has the largest momentum relative to earth's size? a.) a tightrope walker crossing Niagara falls b.) a pickup truck speeding along a highway c.) a Mack truck parked d.) the science building on campus e.) a mouse running across your room

b.) a pickup truck speeding along a highway

A karate chop is more effective if one's hand... a.) follows through upon impact b.) bounces upon impact c.) extends the time upon impact

b.) bounces upon impact

If all people, animals, trains and trucks all over the world began to walk or run towards the east, (opposite the direction of the earth's spin) then... a.) earth's spin wouldn't be affected at all b.) earth would spin a bit slower c.) earth would spin a bit faster

b.) earth would spin a bit slower

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... a.) the same as the magnitude of momentum of either car before collision b.) greater than c.) less than d.) none

b.) greater than

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the stopping force is... a.) greater with the haystack b.) greater with the brick wall c.) both the same

b.) greater with the brick wall

A softer landing occurs when a falling object bounces from a surface... a.) quickly b.) in an extended time c.) either d.) neither

b.) in an extended time

When a boxer moves into an oncoming punch, the force experienced is... a.) no different, but timing is different b.) increased c.) decreased d.) all of the above

b.) increased

An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will... a.) move in the opposite direction at a higher speed b.) move in the opposite direction at a lower speed c.) move 20 m/s d.) none

b.) move in the opposite direction at a lower speed

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... a.) zero b.) twice c.) 4x as much d.) unchanged

b.) twice

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... a.) less than 1 unit b.) more than 1 unit c.) 1 unit d.) need more info

c.) 1 unit

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... a.) 1/2 m/s b.) 2/5 m/s c.) 5/6 m/s d.) 6/5 m/s e.) 1 m/s

c.) 5/6 m/s

The change in momentum that occurs when a 1 kg ball travelling at 4 m/s strikes on a wall and bounces back at 2 m/s is... a.) 2 kg m/s b.) 4 kg m/s c.) 6 kg m/s d.) 8 kg m/s

c.) 6 kg 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? a.) 4 m/s b.) 5 m/s c.) 6 m/s d.) 8 m/s e.) none

c.) 6 m/s

Whether a truck comes to a stop by crashing into a haystack or a brick wall, the impulse is... a.) greater with the haystack b.) greater with the brick wall c.) both the same

c.) 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 towards you at the same speed? a.) car b.) wall c.) both the same d.) need more info

c.) both the same

A cannon recoils while firing a cannonball. The speed of the cannon's recoil is relatively small because the... a.) force against the cannon is smaller than against the ball b.) momentum is mainly concentrated in the cannonball c.) cannon has much more mass than the cannonball d.) momentum of the cannon is smaller

c.) cannon has much more mass than the cannonball

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... a.) doesn't change b.) increases c.) decreases d.) need more info

c.) decreases

Which has the greatest momentum when moving? a.) container pump b.) a bullet c.) either of these depending on speed

c.) either of these depending on speed

The total momentum of a flock of identical birds could be zero only if the birds are... a.) taking off from the ground b.) very tired and coming down to rest c.) flying in different directions d.) flying in the same direction

c.) flying in different directions

If you can't avoid being hit by a fast-moving object, you'll suffer a smaller contact force if you can extend that force over a... a.) shorter time b.) both the same c.) longer time

c.) longer time

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... a.) speed b.) acceleration c.) momentum d.) all e.) none

c.) momentum

A golf ball moving forward with a 1 unit of momentum strikes and bounces backwards 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... a.) less than 1 unit b.) 1 unit c.) more than 1 unit d.) not enough info

c.) more than 1 unit

If a monkey floating in outer space throws his hat away, the hat and the monkey will both... a.) move away from each other at the same speed b.) move a short distance and then go faster c.) move away from each other but at different speeds d.) come to a stop after a few minutes e.) move a short distance then slows down

c.) move away from each other but at different speeds

A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact. The boat... a.) does not move by this wind impact b.) moves, but in the opposite direction of the wind impact force c.) moves in the direction of the wind impact force

c.) moves in the direction of the wind impact force

You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact? a.) the bug b.) your car c.) the same

c.) the same

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force on her hand is... a.) less than the force applied to the cement block b.) zero c.) the same as d.) need more info

c.) the same as

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... a.) force of contact is reduced b.) relative velocity is less c.) time of contact is increased d.) time of contact is decreased e.) none

c.) time of contact is increased

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet? a.) zero b.) half the sum of their original momentums c.) twice d.) need more info

c.) twice

A car travelling along the highway brakes to a stop over a certain distance. More braking force is required if the car has... a.) more mass b.) more momentum c.) less stopping distance d.) all e.) none

d.) all

A red car has a head-on collision with an approaching blue car with the same magnitude of momentum. A green car driving with the same momentum as the other cars collides with an enormously massive wall. Which of the three cars will experience the greatest impulse? a.) red car b.) green car c.) blue car d.) all

d.) all

The force on a dropped apple hitting the ground depends on... a.) whether or not the apple bounces b.) the time of contact with the ground c.) the speed of the apple just before it hits d.) all of the above

d.) all of the above

A falling 1 N apple hits the ground with a force of about... a.) 1 N b.) 4 N c.) 2 N d.) 10 N e.) need more info

e.) need more info