physical science chapter 3 quizzes
A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball initially at rest. After the putty sticks to the ball, both move with a combined momentum of
1 unit.
What is the speed of a 6-kg ball with a momentum of 72 kg m/s?
12 m/s
A bow is drawn so that it has 40 J of potential energy. When the arrow is fired its kinetic energy is ideally
40 J.
A music console is pushed 2 m by a force of 20 N. The work done on the console is
40 J.
A boxer punches a sheet of paper in midair from rest to a speed of 40 m/s in 0.05 s. If the mass of the paper is 0.01 kg, the force of the punch on the paper is
8.0 N.
The impulse-momentum relationship is a direct result of
Newton's second law.
When you simultaneously drop a light tennis ball and a heavy bowling ball, they hit the floor
at the same speed.
An open freight car rolls friction-free along a horizontal track in vertically pouring rain. As water accumulates in the car, its speed
decreases.
Whereas impulse involves the time that a force acts, work involves the
distance that a force acts.
The unit kilowatt-hour is a unit of
energy.
The force that accelerates a rocket in outer space is exerted on the rocket by the
exhaust gases.
When Freddy Frog drops vertically from a tree onto a horizontally-moving skateboard, he doesn't slip off the skateboard because of
friction between his feet and the board.
If you push an object twice as far while applying the same force, you do
twice as much work.
The force of a falling apple hitting the ground depends upon
(all of the above) the time of contact with the ground. the speed of the apple just before it hits the ground. whether or not the apple bounces.
Padded dashboards in cars are safer in an accident than non- padded ones because a person hitting the dash has
(both of these) decreased contact force. increased time of contact.
When a 100-kg astronaut ejects 0.1 kg of gas at a speed of 50 m/s from her propulsion pistol, her recoil speed is
0.05 m/s.
Two identical freight cars roll without friction towards each other on a level track. One car rolls at 2 m/s and the other car rolls at 1 m/s. After the cars collide, they couple and roll together with a speed of
0.5 m/s.
Two identical gliders slide toward each other on an air track. One glider moves at 1 m/s and the other glider moves at 2 m/s. They collide, stick, and move at
1/2 m/s.
A 1-kg chunk of putty moving at 1 m/s collides and sticks to a 5-kg bowling ball that is initially at rest in space. The bowling ball and putty are then set in motion with a speed of
1/6 m/s.
A 5-kg fish swimming at 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the larger fish after lunch is
1/6 m/s.
Consider 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, which has a mass of 5 kg and is at rest. If they stick upon collision the combined-glider speed will be
1/6 m/s.
A melon is tossed straight upward with 100 J of kinetic energy. If air resistance is negligible the melon will return to its initial level with a kinetic energy of
100 J.
What is the mass of a ball moving at 4 m/s with a momentum of 48 kg m/s?
12 kg
A car moves 4 times as fast as another identical car. Compared with the slower car, the faster car has
16 times the kinetic energy.
A car moving at 50 km/h skids 20 m with locked brakes. How far will it skid if its initial speed is 150 km/h?
180 m
A 2-kg mass that weighs 20 N has 40 J of potential energy relative to the ground. What is its height?
2 M
If you exert 100 J to lift a box in 50 s your power output is
2 W.
When the input piston of a hydraulic press is depressed 20 cm, the output piston is observed to move 1 cm. An input force of 1 N can raise no more than
20 N.
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 lunch is
5/6 m/s.
In raising a 5000-N piano with a pulley system, for every 1 m of rope pulled down, the piano rises 0.1 m. Ideally, this means the force needed to lift the piano is
500 N.
Which has the greater momentum when moving?
a bullet or container ship, either depending on the speed
Which has the greater kinetic energy?
a car of half the mass traveling at 60 km/h
When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the contact time is about 10 times more than for a stiff-legged landing and the average force your body experiences is reduced by
about 10 times.
Which of these two collisions is more damaging; driving into a concrete wall with no "give," or colliding head-on with an identical car moving toward you at your same speed?
both the same
While driving down the highway a lovebug spatters onto your windshield. Which undergoes the greater change in momentum during the time of contact?
both the same time
The bob of a simple pendulum has its maximum kinetic energy at the
bottom of its swing.
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
doubled.
A straw is used for a pea shooter. When you blow through the straw the speed of the emerging pea will be greater if the straw is
full length.
A heavy truck and a small car roll down a hill at the same speed and need to stop in the same amount of time. Compared with the force to stop the car, the force needed to stop the truck is
greater.
A clerk can lift containers a vertical distance of 1 m, or roll them up a 2-m-long ramp to the same elevation. With the ramp, the applied force needed is
half as much.
A block of ice sliding down an incline has half its maximum kinetic energy
half-way down.
When a bus brakes to a stop its kinetic energy transforms to
heat.
A circus diver drops from a high pole into water far below. When he is half-way down
his potential energy is halved. . his kinetic and potential energies are equal. he has gained an amount of kinetic energy equal to half his initial potential energy. (all of the above)
The speed of a bullet fired from a gun will be about the same as the speed of the recoiling gun
if the masses of the bullet and gun are equal.
The change in momentum of an object is equal to the
impulse that acts on it.
A cannonball fired from a long-barrel cannon will have a greater muzzle velocity because the cannonball receives a greater
impulse.
When a boxer moves into an oncoming punch, the force experienced is
increased.
The massive ram of a pile driver falling from rest strikes a pile with a speed that depends on the
initial height of the ram. initial potential energy of the ram. distance the ram falls. all of the above
According to the impulse-momentum relationship Ft = change in mv, a falling bungee jumper has momentum which is reduced by the force Fexerted by the bungee cord. If v is the speed of the jumper, then m in the equation is the mass of the
jumper.
Compared to a recoiling rifle, the bullet that is fired has a greater
kinetic energy.
An object may have potential energy because of its
location.
A 1-kg ball dropped from a height of 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about
more than 2.0 J.
A boulder is dropped onto mud and plows into it a certain distance. If it hits with three times as much speed, the distance it plows into the mud will likely be
more than three times as deep.
A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact. The boat
moves in the direction of the wind impact force.
The power expended for a barbell raised 2.0 m in 2 s is
not enough information
Which of the following has the largest momentum relative to Earth?
pickup truck speeding along a highway
Which requires more work on the brakes of a car?
slowing down from 100 km/h to 70 km/h
It is correct to say that impulse is equal to
the change in momentum.
A ball rolling down an incline has its maximum potential energy at
the top.
The conservation of momentum is most closely related to Newton's
third law
To catch a fast-moving softball with your bare hand, you extend your hand forward just before the catch and then let the ball ride backward with your hand. Doing this reduces the catching force because the
time of catch is increased.
Strictly speaking, if any electrical device in an automobile is turned on (such as an air conditioner or even headlights), more fuel is consumed by the engine. This statement is
true.
A 1000-kg car and a 2000-kg car are hoisted the same vertical distance in a service station. Raising the more massive car requires
twice as much work.
If you do work on an object in half the time, your power output is
twice.
Power is defined as the
work done divided by the time to do the work.
