physics chapter 6

When a falling firecracker explodes, the momenta of its pieces _______.

vectorally add to equal the initial momentum of the firecracker

When two vehicles collide, momentum is conserved _______.

whether the collision is elastic or inelastic

Follow through is important in golf because it results in a greater _______.

impulse on the ball

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

increased time of impact.

A slowly moving ship can have a greater momentum than a fast-moving racing car when _______.

its mass times velocity is greater than that of the car

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

more than 1 unit.

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

more.

An astronaut , floating alone in outer space, throws a baseball. If the ball floats away at a speed of 20 meters per second, the astronaut will

move in the opposite direction, but at a lower speed.

Judy (mass 44 kg ), standing on slippery ice, catches her leaping dog (mass 15 kg) moving horizontally at 3.8 m/s. Find the speed of Judy and her dog after the catch.

v = 0.97 ms

A railroad diesel engine weighs four times as much as a freight car. If the diesel engine coasts at 5.8 km/h into a freight car that is initially at rest, find the speed of the coupled cars.

v = 4.6 kmh

A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball that is initially at rest on a frictionless surface. The speed of the putty thereafter is...

1/6 m/s.

An ostrich egg of mass m is tossed at a speed v into a sagging bed sheet and is brought to rest in a time t. Find the force acting on the egg when it hits the sheet.

F = mv/t

Which of the following has the largest momentum relative to the Earth's surface? a tightrope walker crossing Niagara Falls a Mack truck parked in a parking lot a dog running down the street the Science building on campus a pickup truck speeding along a highway

a pickup truck speeding along a highway

A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has... less stopping distance. more mass. more momentum. all of these

all of these

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

0

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

1 unit.

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, the magnitude of the jumper's average deceleration is about

1.5 g.

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

1/3 m/s.

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

16 kg

What is the momentum of a 58-kg carton that slides at 5.0 m/s across an icy surface? Momentum = mv

290 kg⋅ms

How much impulse stops a 60-kg carton sliding at 5.0 m/s when it meets a rough surface? Impulse = change in momentum: Ft=Δmv

300 N⋅s

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

5/6 m/s.

The change in momentum, in kg m/s, that occurs when a 1.0 kg ball travelling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is

6.

What impulse occurs when the force of 15 N acts on the cart for the time 6.0 s ? Impulse = Ft

90 kg⋅ms

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

Earth would spin a bit slower.

Joanne drives her car with a mass of 1000 kg at a speed of 17 m/s . Find a road friction force that is need to bring her car to a halt in 14 s .

F = 1200 N

An ostrich egg of mass m is tossed at a speed v into a sagging bed sheet and is brought to rest in a time t. If the mass of the egg is 1.3 kg , its initial speed is 2.3 m/s, and the time to stop is 0.20 s, find the average force on the egg.

F = 15 N

The conservation of momentum is most closely related to...

Newton's 3rd law.

Which would produce more force: 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

When a cannonball is fired from a cannon, the momentum of the recoiling cannon is momentarily _______.

equal and opposite to the momentum of the fired cannonball

A boxer rides with the punch so as to reduce _______.

force

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.

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.

Cassy can get more force on the bricks she breaks with a blow of her bare hand when _______.

her hand is made to bounce from the bricks

A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will have a greater... momentum. acceleration. speed. all of these none of these

none of these

When a big fish swims into an oncoming smaller fish and swallows it, the momentum of the two-fish system _______.

remains the same

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

stopping time is longer on the carpet.

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

the change in momentum it produces.

The quantity that is called impulse can be measured by _______

the product of force and time

A lunar vehicle is tested on Earth at a speed of 10 km/h. When it travels as fast on the Moon, is its momentum more, less, or the same?

the same

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 a weapon

the target would be safer than the shooter.

When a cue ball strikes an 8 ball head-on in a game of pool, the cue ball _______.

transfers its momentum to the 8 ball

Comic-strip hero Superman meets an asteroid in outer space and hurls it at 840 m/s , as fast as a bullet. The asteroid is a thousand times more massive than Superman. In the strip, Superman is seen at rest after the throw. Taking physics into account, what would be his recoil velocity?

v = 8.4×105 ms

A 3.00-kg blob of putty moving at 3.80 m/s slams into a 4.40-g blob of putty at rest. Calculate the speed of the two stuck-together blobs of putty immediately after colliding. Conservation of momentum: mv(before)=mv(after)

v=3.79 ms