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WorksheetsEnergy Review
Total questions: 35
Worksheet time: 35mins
In physics, work is defined as
force times time
force divided by time
force times distance
force divided by distance
distance divided by time
How many joules of work are done on an object when a force of 10 N pushes it 5 m?
50 J
10 J
5 J
2 J
1 J
How much power is required to do 100 J of work on an object in 2 seconds?
200 W
100 W
50 W
2 W
0 W
Potential energy is the energy an object has because of its
speed
location
size
temperature
density
Suppose a moving car has 2000 J of kinetic energy. If the car's speed doubles, how much kinetic energy would it then have?
8000 J
6000 J
4000 J
2000 J
1000 J
An arrow in a bow has 70 J of potential energy. Assuming no loss of energy due to heat, how much kinetic energy will it have after it has been shot?
140 J
70 J
50 J
35 J
0 J
A woman can lift barrels a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. If she uses the ramp, the applied force required is
one quarter as much
half as much
twice as much
four times as much
the same amount
It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box?
4 N
10 N
40 N
160 N
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
less than 100 J
more than 100 J
100 J
not enough information given
Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h?
the 30 km/h car
the 60 km/h car
both have the same kinetic energy
A person on a roof throws one ball downward and an identical ball upward at the same speed. The ball thrown downward hits the ground with 100 J of kinetic energy. Ignoring air friction, with how much kinetic energy does the second ball hit the ground?
100 J
200 J
less than 100 J
more than 200 J
A 10-N object moves at 1 m/s. Its kinetic energy is
0.5 J
1 J
10 J
more than 10 J
A pulley has two supporting strands. In order to use it to lift a load 1 meter, the person pulling will have to pull a distance of
4 m
2 m
1 m
1/2 m
1/4 m
The ratio of useful work output to total work input is called the
fulcrum
pivot point
efficiency
mechanical advantage
lever arm
A certain jack has a theoretical mechanical advantage of 500. However, due to frictional forces, the actual mechanical advantage is only 100. What is the efficiency of the jack?
50,000
500
50
5
1/5
Three identical balls are thrown from the top of a building, all with the same initial speed. The first ball is thrown horizontally, the second at some angle above the horizontal and the third at some angle below the horizontal. Neglecting air resistance, rank the speeds of the balls as they reach the ground, from fastest to slowest.
1, 2, 3
2, 1, 3
3, 1, 2
all three balls strike the ground at the same speed
Bob, of mass m, drops from a tree limb at the same time that Esther, also of mass m, begins her descent down a frictionless slide. If they both start at the same height above the ground, which of the following is true about their kinetic energies as they reach the ground?
Bob's kinetic energy is greater than Esther's.
Esther's kinetic energy is greater than Bob's.
They have the same kinetic energy.
The answer depends on the shape of the slide.
If you lift one load up two stories, how much work do you do compared to lifting one load up only one story?
four times as much
twice as much
the same amount
one half as much
one quarter as much
The amount of potential energy possessed by an elevated object is equal to
the force needed to lift it
the distance it is lifted
the power used to lift it
the work done in lifting it
the value of the acceleration due to gravity
How much work is done on a 50-N rock that you carry horizontally across a 10-m room?
500 J
50 J
10 J
5 J
0 J
How much farther will a car traveling at 50 m/s skid in coming to rest than the same car traveling at 25 m/s?
five times as far
four times as far
twice as far
the same distance
half as far
Energy is changed from one form to another with no net loss or gain.
always true
always false
sometimes true
As a pendulum swings back and forth
potential energy is transformed into kinetic energy
kinetic energy is transformed into potential energy
at the lowest part of its swing, its energy is all kinetic
at the end points of its swing, its energy is all potential
All simple machines ideally work on the principle that
impulse equals momentum change
force equals mass times acceleration
kinetic energy transforms into potential energy
total momentum before a collision equals total momentum after the collision
work input equals work output
A pulley system can
change the direction of a force
multiply the force
increase the amount of work done
A frictionless inclined plane is 6 m long and rests on a wall that is 2 m high. How much force is needed to push a block of ice weighing 300 N up the plane?
600 N
300 N
200 N
100 N
50 N
A machine puts out 100 watts of power for every 1000 watts put into it. The efficiency of the machine is
10%
50%
90%
110%
The energy of a raindrop falling toward the ground is
all potential energy
all kinetic energy
a combination of potential and kinetic energy
elastic potential energy
The gravitational potential energy of an object does not depend on
the object's mass
the object's height
the object's speed
acceleration due to gravity
An object launched straight up with speed v reaches a height h. What speed would it need if it were to reach a new height of 2h?
v/2
2 v
2v
4v
How much power is required to lift a 1.5 kg bucket a height of 18 m in 9.0 seconds?
3.0 W
13.5 W
29 W
243 W
It takes 5.00 J of work to push a 0.020 kg dart into a spring loaded dart gun. The spring is compressed 8.00 cm. What is the spring constant?
62.5 N/m
125 N/m
781 N/m
1560 N/m
A spring is compressed a distance z and fires a mass straight upward to a height of h. How much should the spring be compressed to fire the same mass to a height of 2h?
z/2
2 z
2z
4z
A car traveling at 10 m/s can stop a distance of 20 meters. When traveling at 30 m/s the same car's brakes will stop it in a distance of
35 m
60 m
90 m
180 m
A wagon is pulled 8.0 m along level ground by applying a force of 100.0 N at an angle of 60.0° above the horizontal. How much work was done?
80 J
400 J
480 J
690 J
800 J
