Multiple Choice Identify the
choice that best completes the statement or answers the question.


1.

In physics, work is defined as
a.  force times time.  b.  force divided by distance.  c.  distance divided by
time.  d.  force divided by time.  e.  force times
distance. 


2.

f you lift two loads up one story, how much work do you do compared to lifting
just one load up one story?
a.  One quarter as much  b.  One half as much  c.  The same
amount  d.  Twice as much  e.  Four times as
much 


3.

If you lift one load up two stories, how much work do you do compared to lifting
one load up only one story?
a.  One quarter as much  b.  One half as much  c.  The same
amount  d.  Twice as much  e.  Four times as
much 


4.

If Nellie Newton pushes an object with twice the force for twice the distance,
she does
a.  twice the work.  b.  the same work.  c.  four times the
work.  d.  eight times the work. 


5.

The unit of work is the
a.  watt.  b.  meter.  c.  joule.  d.  newton.  e.  second. 


6.

Power is defined as the
a.  force on an object divided by the time the force acts.  b.  work done times the
time taken to do that work.  c.  work done on an object divided by the time
taken to do the work.  d.  distance divided by the time taken to move that
distance.  e.  force on an object times the distance the object
moves. 


7.

The unit of power is the
a.  newton.  b.  meter.  c.  joule.  d.  second.  e.  watt. 


8.

Potential energy is the energy an object has because of its
a.  density.  b.  size.  c.  location.  d.  speed.  e.  temperature. 


9.

The amount of potential energy possessed by an elevated object is equal to
a.  the power used to lift it.  b.  the distance it is lifted.  c.  the force needed to
lift it.  d.  the work done in lifting it.  e.  the value of the acceleration due to
gravity. 


10.

Kinetic energy of an object is equal to
a.  its mass multiplied by its acceleration squared.  b.  one half the product
of its mass times its speed squared.  c.  its mass multiplied by its
speed.  d.  one half the product of its mass times its speed.  e.  its mass multiplied
by its acceleration. 


11.

How much farther will a car traveling at 100 km/s skid than the same car
traveling at 50 km/s?
a.  Half as far.  b.  The same distance.  c.  Twice as
far.  d.  Four times as far.  e.  Five times as
far. 


12.

An arrow in a bow has 70 J of potential energy. Assuming no loss of energy to
heat, how much kinetic energy will it have after it has been shot?
a.  0 J  b.  35 J  c.  50
J  d.  70 J  e.  140 J 


13.

Energy is changed from one form to another with no net loss or gain.
a.  Sometimes true  b.  Always false  c.  Always
true 


14.

As a pendulum swings back and forth
a.  at the end points of its swing, its energy is all potential.  b.  at the lowest part
of its swing, its energy is all kinetic.  c.  kinetic energy is transformed into potential
energy.  d.  potential energy is transformed into kinetic energy.  e.  all of the
above 


15.

When a car’s speed triples, its kinetic energy
a.  remains the same.  b.  triples.  c.  increases by four
times.  d.  increases by nine times.  e.  none of the
above 


16.

A woman can lift barrels a vertical distance of 1 meter or can roll them up a
2meter long ramp to the same elevation. If she uses the ramp, the applied force required is
a.  as much.  b. 
as much.  c.  the same amount.  d.  2 times as much.  e.  4 times as
much. 


17.

A job is done slowly, and an identical job is done quickly. Both jobs require
the same amount of work but different amounts of
a.  energy.  b.  power.  c.  both A and
B  d.  none of the above 


18.

Which requires more work: lifting a 70kg sack vertically 2 meters or lifting a
35kg sack vertically 4 meters?
a.  Lifting the 70 kg sack  b.  Lifting the 35 kg sack  c.  Both require the
same amount of work. 


19.

A ball is thrown into the air with 100 J of kinetic energy, which is transformed
to gravitational potential energy at the top of its trajectory. When it returns to its original level
after encountering air resistance, its kinetic energy is
a.  100 J.  b.  more than 100 J.  c.  less than 100
J.  d.  Not enough information given. 


20.

An object that has kinetic energy must be
a.  at rest.  b.  falling.  c.  moving.  d.  elevated. 


21.

An object that has kinetic energy must have
a.  acceleration.  b.  a force applied to maintain
it.  c.  momentum.  d.  none of the
above 


22.

Which has greater kinetic energy, a car traveling at 30 km/h or a
halfasmassive car traveling at 60 km/h?
a.  The 60 km/h car  b.  Both have the same kinetic
energy.  c.  The 30 km/h car 


23.

An object at rest may have
a.  energy.  b.  speed.  c.  velocity.  d.  momentum.  e.  none of the
above 


24.

If the velocity of a moving object doubles, then what else doubles?
a.  acceleration.  b.  kinetic energy.  c.  momentum.  d.  all of the above  e.  none of the
above 


25.

The ratio of output force to input force of a simple machine is called the
a.  fulcrum.  b.  efficiency.  c.  pivot
point.  d.  lever arm.  e.  mechanical
advantage. 


26.

Consider molecules of hydrogen gas and molecules of heavier oxygen gas that have
the same kinetic energy. The molecules with the greater speed are
a.  hydrogen.  b.  Both have the same speed.  c.  oxygen. 


27.

How much power is required to do 40 J of work on an object in 5 seconds?
a.  0 W  b.  5 W  c.  8
W  d.  40 W  e.  200 W 


28.

How much work is done on a 20N crate that you lift 2 m?
a.  0 J  b.  1 J  c.  2
J  d.  20 J  e.  40 J 


29.

How much power is expended if you lift a 60 N crate 10 meters in 1
second?
a.  0 W  b.  6 W  c.  10
W  d.  60 W  e.  600 W 


30.

Suppose a moving car has 3000 J of kinetic energy. If the car's speed
doubles, how much kinetic energy will it then have?
a.  1000 J  b.  1500 J  c.  3000
J  d.  6000 J  e.  12,000 J 


31.

If Kelly the skater's speed increases so he has three times the momentum,
then his kinetic energy increases by
a.  one third times.  b.  three times.  c.  nine
times.  d.  none of the above (KE remains the same). 


32.

A 60N object moves at 1 m/s. Its kinetic energy is
a.  1 J.  b.  3 J.  c.  60
J.  d.  more than 60 J. 

True/False Indicate whether the
statement is true or false.


33.

In physics, the amount of work done on an object is the product of the force
exerted on the object times the time the object moves.


34.

The unit of work is called the joule.


35.

The rate at which work is done is called energy.


36.

The unit of power is the watt.


37.

The rate at which work is done is called power.


38.

The energy an object has by virtue of its location is its potential
energy.


39.

The energy an object has by virtue of its motion is its kinetic energy.


40.

When we carry an object across a room, without lifting it or setting it down, we
do no physical work on it.


41.

More power is needed to carry a heavy suitcase slowly up a flight of stairs than
to carry the suitcase quickly up the same flight of stairs.


42.

Energy transforms from one form to another with no net loss or gain.

Essay


43.

You do work on something when you lift it against gravity. How does this work
relate to gravitational potential energy? If the lifted object is released, what becomes of this
energy? Be sure to define all terms that you use.


44.

Discuss how energy conservation applies to a pendulum. Where is potential energy
the most? The least? Where is kinetic energy the most? The least? Where is it moving the fastest?
Stopped?

Problem


45.

What is the work done in lifting 60 kg of blocks to a height of 20 m?


46.

A toy cart moves with a kinetic energy of 10 J. If its speed is doubled, what
will its kinetic energy be?


47.

In raising a 3000N piano with a pulley system, it is noted that for every 2 m
of rope pulled down, the piano rises 0.2 m. Ideally, what force is needed to lift the piano?


48.

A car traveling at 50 km/h will skid 20 m when its brakes are locked. If the
same car is traveling at 150 km/h, what will be its skidding distance?


49.

A 30kg girl runs up the staircase to a floor 5 m higher in 8 seconds. What is
her power output?


50.

At what height does a 1000kg mass have a potential energy of 1 J relative to
the ground?


51.

The 4.0kg head of an ax is moving at 4.0 m/s when it strikes a log and
penetrates 0.01 m into the log. What is the average force the blade exerts on the log?


52.

An anvil hanging vertically from a long rope in a barn is pulled to the side and
raised like a pendulum 1.60 m above its equilibrium position. It then swings to its lowermost point
where the rope is cut by a sharp blade. The anvil then has a horizontal velocity with which it sails
across the barn and hits the floor, 10.0 m below. How far horizontally along the floor will the anvil
land?
