Download Energy and Power Test Study Guide – answer key

Name: ________________________ Date:__________ Period:_____ Bin# _____
Energy and Power Test Study Guide – answer key
1. According to the picture below, at which point has the greatest kinetic energy? D
2. According to the picture below what two points has the greatest potential energy? A
and G
D
C
B
A
E
F
G
3. A person is using a force of 300N to push a cart. How much power does the person
need to push the cart a distance of 5m in 20s? 75 watts (Power = Work ÷ time)
4. In competition, weightlifter 1 lifts 150 kg weight from the floor. Weightlifter 2 also lifts
150kg weight to the same height above the floor, but takes a longer time to do so.
Write a statement that describes the work done and the power used by the
weightlifters? Weightlifter 2 does the same amount of work and uses less power than
weightlifter 1.
5. If kinetic energy of a 20kg mass is 160J, what is its speed? ( KE = 1/2m X V2 ) = 4 m/s2
6. What is the amount of work done when a force of 10N moves a 20kg mass of 8 meters?
80J ( Work = force X distance)
7. In a physics lab, an applied force is exerted parallel to a plane inclined at 30° in order to
displace a cart up the incline. This is an example of which type of work? Positive work
8. What is the kinetic energy of a bicycle with a mass of 25kg traveling at a velocity of
4m/s? ( KE = 1/2m X V2 ) = 200J
9. A force of 15N is used to push a box along the floor of 3 meters. How much work is
done? 45J ( Work = force X distance)
10. Mike is cutting the grass using a human powered lawn mower. He pushed the mower
with a force of 45N directed at an angle of 41° below the horizontal direction. Calculate
the work that Mike does on the mower in pushing it 9.1 m across the yard. 5J ( Work =
force X distance) 409.5 J
11. What is the displacement of the cross-country team if they begin at the school, run 8
miles and finishes back at the school? 0
12. A rock climber weighs 225N and is carrying a backpack that weighs 25N. How much
total work has been done after she climbs 6 m? ( Work = force X acceleration due to
gravity X distance) 14,700 J
13. A student leaving the school walks 5 km north and then walks 2.0 km south. What is the
student’s displacement? 3.0 Km northward
14. Identify whether the following example is potential energy or kinetic energy:
Name: ________________________ Date:__________ Period:_____ Bin# _____
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a. A person on a sled poised at the top of a hill __Potential energy___
b. A steel dam holding back a reservoir of water __potential energy_____
c. A woman swings a golf club _____Kinetic energy___________
The law of conservation of energy states that when one form of energy is converted into
matter, __no energy is destroyed in the process_
What is the rate in which work is done? Joules
What does gravitational potential energy depend on? height
What is kinetic energy? Energy associated with motion
What is potential energy? Energy that is stored
Give an example of potential energy? A book on a shelf
Give an example of kinetic energy? A rollercoaster going down a hill
What is the power of a light bulb that converts electrical energy at a rate of 200 joules
per second? (Power = Work ÷ time) 200 watts
What is the formula for power? Power = Work ÷ time
What is the formula for work? Work = force X distance
What is thermal energy? The total energy of the particles in an object
What is the unit for energy? Joules
What is the unit for work? Joules
What is the work done against gravity? Work = force X acceleration due to gravity X
distance
What is the acceleration rate due to gravity? 9.8 m/s2
What is energy? The ability to do work