Physics Exam 2 Practice

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

1 unit

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

1/6 m/s

A motorcycle mmoving at 50 km/h skids 10 m with locked brakes. How far wil it skid with locked brakes when travleing at 150 km/h

90 m

A motorcycle moving at 50 km/h skids 10 m with locked brakes. How far will it skid with locked brakes when traveling at 150 km/h?

90 m

A machine puts out 100 Watts of power for every 1000 watts put into it. The efficiency of the machine is

90%

When wind encounters a wind turbine that produces energy, wind speed on the downside of the blades is

Newton's 3rd law

Which of the following has the large momentum relative to earth's surface?

a pickup truck speeding along a highway

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

equals the momentum of the firecrackers at the time of burst

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

equals to the momentum of the firecracker at the time of the burst

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

exhaust gases

How far must one travel to escape Earth's gravitational field?

forget it; you cant's travel far enough

Two identical arrows, one with twice the speed of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

four times as far

The work you do when pushing a shopping cart twice as far while applying twice the force is

four times as much

Two identical gold carts move at different speed. The faster cart has twice the speed and therefore has

four times the kinetic energy

Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard. The reason he doesn't slip off the skateboard is due to

friction between his feet and the board

The conservation of momentum is most closely to related to

geothermal energy

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

greater

An object that has kinetic energy must be

moving

If an all-electric car has kinetic energy, then it also must have

need more information

Which of these is not a form of solar energy?

none of the above

No work is done by gravity on a bowling ball that rolls along a bowling alley because

nor force acts on the ball

If the Sun became twice as massive, your attraction to the Sun would double and your weight as measured on Earth would

not change

The force of Earth's gravity on a capsule in space will lessen as it moves farther away. If the capsule moves to twice its distance, the force toward Earth becomes

one-fourth

If your mass, the mass on Earth, and the mass of everything in the solar system were twice as much as it is now, yet everything stayed the same size, your weight on Earth would

quadruple

Earth is presently accelerating toward the Sun (centripetal acceleration). If the Sun collapsed into a black hole, this acceleration would

remains the smae

Earth's primary energy source is

sun

Two identical freight cars roll without friction (one at 1 m/s, the other at 2 m/s) towards each other on a level track. They collide, couple togther, and roll away in the direction of

the faster car

A work done in pushing a TV set a distance of 2 m with an average force of 20 N is

40 J

A toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed using 1000 J of work, is

50 W

A piece of taffy slams and sticks to an identical piece of taffy at rest. The momentum of the combined pieces after the collision is the same as before the collision, but this is not true of the kinetic energy, which partyly degrades into heat. What percentage of the kinetic energy is lost to heat or other forms of energy?

50%

A piece of taffy slams into and sticks to an identical piece of taffy at rest. The momentum of the combined pieces after the collision is the same as before the collision, but this is not true of the kinetic energy, which partly degrades into heat. What percentage of the kinetic energy becomes heat?

50%

Danny Diver weighs 500 N and steps off a diving board 10 m above the water. Danny hits the water with kinetic energy of

5000 J

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?

6 m/s

A 2-kg ball is held 4 m above the ground. Relative to the ground its potential energy is

80 J

Earth's gravitational field extends

both inside and outside the Earth and throughout the entire universe

About 40 J is required to push a crate 4 m across a floor. If the push is in the same direction as the motion of the crate, the force on the crate is about

10 N

A machine puts out 100 watts of power fro every 1000 watts put into it. The efficiency of the machine is

10%

A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above Earth's Surface. How much is her weight there?

100 N

A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above Earth's surface. How much is her weight there?

100 N

Phil applies 100 N to a pulley system and raises a load one-tenth of his downward pull. Ideally, the weight of the load is

1000 N

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

16 kg

The power expended doing 100 J of work in 50 s is

2 W

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

2 kg 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

2/3 m/s

One kilowatt-hour represents

3.6 million joules

A hydraulic press, like an inclined plane, is capable of increasing energy

Always false

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

Earth would spin a bit slower

Strictly speaking, more fuel is consumed by your car if the air conditioner, headlights, or even a radio is turned on. This statement is

True

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

about 1/10 as great

A feather an a coin dropped in a vacuum fall with equal

accelerations

A cannonball has more kinetic energy than the recoiling cannon from which it is fired because the force on the ball

acts over a longer distance

The ram of a pile driver drops onto the top of an iron beam, driving it partway into the ground. The distance that the beam sinks into the ground depends on the

all of the abouve

A circus diver drops from a high pole into water far below. When he is halfway down

all of the above

A moving object has

all of the above

An outcome of universal gravitation is that a. prediction and discovery of planets b. its discovery prompted other laws of nature c. planets aren't cubes with sharp corners d. all of the above

all of the above

You can experience weight

all of the above

An outcome of universal gravitation is that

all of the baove

Rate this statement: No force due to Earth's gravity acts on astronauts inside the orbiting space station.

always false

When properly used, a hydraulic press, like a wheel and axle, is capable of multiplying force input.

always true

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

The bob of a simple pendulum has its maxium kinetic energy at the

bottom of its swing

When a cannon is fired, it recoils as the cannonball is set in motion. The cannon and cannonball ideally acquire equal

but opposite amounts of momentum

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

cannon has much more mass than the cannonball

A common pulley acts similar to a

common lever

If Earth's radius somehow increased with no change in mass, your weight would

decrease

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

decreased

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

earth would spin a bit slower

If an object is placed exactly halfway between Earth and the Moon, it would fall toward the

earth

A primary differenc between momentum and kinetic energy is

either of the above depending on circumstances

Which is most responsible for Earth's ocean tides?

moon

A 1-kg ball dropped from 2 m rebounds only 1.5 m after hitting the ground. The amont of energy converted to heat is about

more than 2.0 J

According to Newton, the greater the masses of interacting objects, the

greater the gravitational force between them

A clerk can lift cylindrical packages 1 meter vertically, or can roll them up a 2-meter-long ramp to the same elevation. With the ramp, the applied force required is about

half as much

If the mass of Earth somehow increased with no change in radius, your weight would

increase also

As two objects moving toward each other due to gravity get closer, the acceleration of each

increases

The amount of work done on a heavy box carried by Nellie across a room at a constant speed

is none

If the Moon had twice as much mass and still orbits Earth at the same distance, ocean bulges on Earth would be

larger

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

lengthened time of contact

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

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

momentum

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

move away from each other, but a differnt speeds

A ball rolling down an incline has its maximum potential energy at

the top

An asteroid exerts a 360-N gravitational force on a nearby spacecraft. The 360-N force on the spacecraft is directed

toward the asteroid

Two identical arrows, one with twice the kinetic energy of the other, are fired into a bale of hay. Compared with penetration of the slow arrow, the faster arrow penetrates

twice as far

A crate of grapes lifted 10 meters gains 200 J of potential energy. If the same crate is instead lifted 20 meters, its gain in potential energy is

twice as much

In comparison with other fundamental forces, the universal gravitational constant G indicated that gravity is

very weak

In comparison with other fundamental forces, the universal gravitational constant G indicates that gravity is

very weak