1. Distinguish between kinetic and potential energy.
Define machines.
Distinguish between kinetic and potential energy.
Calculate different energies.

2. In one sentence, write what machines do.

3. 1. What do machines do?
Make work easier.

4. 2. How can machines make work easier?
Increase force applied
Increase distance moved
Change direction of force

5. 3. What is work input?
Force and distance you exert on a machine. Eg: Force exerted on handle of oar

6. Force and distance exerted by the machine.
4. What is work output?
Force and distance exerted by the machine.
Eg.: the oars pushing against the water

7. Energy is the ability to do work.
5. What is energy?
Energy is the ability to do work.

8. 6. ____________________ is the energy of _____________.
Kinetic energy
6. ____________________ is the energy of _____________.
motion

9. 7. The formula for kinetic energy is:
KE = ½ m v2

10. 8. What factors affect the amount of kinetic energy?
Doubling mass will double KE.
Doubling velocity will quadruple KE.

11. m = 0.10 kg
KE = ½ m v2
KE = 3.2 J
KE = ½ (0.10) (8.0)2
v = 8.0 m/s
KE = ½ (0.10) (64.0)

12. Potential energy stored position or shape
10. ____________________ is the energy _____________ as a result of _______________________.
Potential energy
stored
position or shape

13. 8. Okay, so what is gravitational potential energy?
GPE depends on an object’s position.
So if the object is on the ground… if the ground is our reference, it is 0 m.

14. The formula for GPE is:
PE = m g h

15. m = 50 kg
PE = m g h
PE = 4000 J
h = 10.0 m
PE = (50kg) (9.8 m/s2) (10.0 m)
g = 9.8 m/s2

16. Do the practice questions on your own and then check with a neighbor!
Then we will check them as a class.
Afterwards, begin on homework: Potential and Kinetic energy calculations.