Work
Power
Potential Energy
Kinetic Energy
Conservation
100
What is the Unit for Work?
Joules (J)
100
What is the unit for power?
Watts
100
What are the units for potential energy?
Joules (J)
100
If the velocity of an object is doubled, what happens to its kinetic energy (increases, decreases, etc.)?
It quadruples!
100
What does the law of conservation of energy state?
Energy cannot be created or destroyed, it just changes forms.
Therefore mechanical energy is the same at all points.
200
If you push an object twice as far without changing the force you pushed it with, what happens to work (increase, decrease, etc.)?
Work doubles!
200
If Mrs. Suchman pushes against the wall with a 50N force for 2 seconds, how much power is she using?
None! No work is done on the wall.
200
What two factors determine the amount of potential energy?
Mass and height
200
An object that has kinetic energy must be
Moving
200
As I lift an object higher I do work on the object. As I do work on the object, the objects increases this type of energy.
Potential energy
300
If a business man carries a briefcase with an upward force of 10N a distance 5 m to the right, how much work does he do on the briefcase?
He does 0J of work on the briefcase because the force is perpendicular to his displacement
300
What are two ways that power can be increased? (Hint: Power = Work / Time)
Increase the amount of work done, or decrease the time in which work is done
300
If you double the height of an object, what happens to its gravitational potential energy?
Gravitational potential doubles as well
300
When does a ball rolling down an incline have maximum kinetic energy (at the top, at the bottom, at the middle of the ramp, etc.)?
At the bottom of the incline
300
How can I calculate the mechanical energy of an object?
PE + KE
400
In the equation W = F d, what do each of the variables/letters represent?
W = work
F = force
d = distance traveled
400
A 50 Newton sack is lifted 2 meters from the ground and a 25 Newton sack is lifted 4 meters. Both were lifted in 10 seconds. Which used up more power?
They are equal!
400
A 5 kg object is held 5 m above the ground. What is its gravitational potential energy?
250 J
400
A pendulum is swinging back and forth. As the pendulum moves from its lowest point to its highest point, its energy transfers from Kinetic Energy to ____________.
Potential energy
400
A ball is released from rest at the top of an incline. What type of energy does it have initially, and what energy does it get converted to?
Potential energy to kinetic energy
500
The direction of the displacement and the direction of the force are PERPENDICULAR TO EACH OTHER. This means that the amount of work done will be ____.
Zero
500
An older man and young boy, who each have the same mass of 60 kg, climbed up the top of the same building. The older man, given his age, walked slowly. The young boy walked up faster.
Who did more work?
Who used up more power?
Same work (same mass, same distance traveled)
More power = boy (climbed faster)
500
Why is potential energy called POTENTIAL energy? What kind of energy is it?
Potential energy is stored energy. An object with PE has the POTENTIAL to do work.
500
Two cars of the same mass are speeding, one with twice the velocity of the other. When they slam on their breaks, which car will require a greater stopping distance, the faster car or the slower car?
The faster car stops in a distance 4 times that of the slower car.
500
Rank the positions from lowest KE to greatest KE.
5 > 1 > 4 > 2 > 3