Energy
Work
Power
Think
Short Answer Questions
100
The kinetic energy of an object increases as its _______________ increases. (gravitational energy, velocity, specific heat)
velocity
100
The SI unit for work is
Joule (J)
100
The SI unit for power is
watts.
100
If a ball is dropped from a tall building, where does it have the greatest potential energy?
Right before it is dropped
200
The SI unit for energy is
Joule (J)
200
The rate at which work is done is called
power.
200
What is the equation for power?
P=W/t
200
If an object has energy, this means that it has the ability to cause ____________. (change, form, Joules)
change.
300
A bus transfers chemical potential energy to _____________ energy so the bus moves.
kinetic
300
The amount of work done when holding a 300 kg barbell above your head for 30 seconds.
No work
300
If a 4 wheeler does 100 J of work in 5 seconds, how much power does the 4 wheeler have?
20 watts
300
Stored energy is called
potential energy.
300
How are work, time, and power related?
Power is the amount of work done per unit of time P=W/t.
400
According to the Law of Conservation of Energy, the total amount of energy in the universe (remains constant, increases, decreases, changes constantly).
remains constant.
400
If a man pulls a sled 20 m through the woods with a force of 10N, what is the work he has done?
200 J
400
Which is more powerful, A truck moving up a hill in 10 seconds, or a truck moving up a hill in 5 seconds.
The faster truck
400
According to the law of conservation of energy, energy can change ___________, but it cannot be created nor destroyed.
form
400
A dump truck, a sports car, and a motorcycle are traveling at the same velocity. Compare their kinetic energies.
Kinetic energy is based on mass and velocity. Given equal velocities, the dump truck has the greatest kinetic energy, because it has the greatest mass. The sports car would be next, then the motorcycle.
500
Increasing the speed of an object ____________ its potential energy. (does not affect, changes, increases, decreases).
does not affect
500
If a hunter carries his injured dog 1500 meters back to his truck with a force of 100 N, what is his total work done?
150,000 J
500
If an Aston Martin travels 100 m with a force of 100 N, in 60 seconds, how much power does the car have?
Approximately 167 watts
500
When you move your foot, your body converts ___________ energy to __________ energy.
potential, kinetic
500
Describe the changes in mechanical energy as you run up a flight of steps.
At the bottom of the steps, your potential energy is 0%. As you run up the steps, your kinetic energy is transferred into potential energy. At the top, your kinetic energy is 0%, and your potential energy is at 100%.
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