I can Define machines Distinguish between kinetic and

I can… Define machines. Distinguish between kinetic and potential energy. Calculate different energies.

In one sentence, write what machines do.

1. What do machines do? Make work easier.

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

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

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

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

6. __________ is the Kinetic energy of _______. motion

7. The formula for kinetic energy is: KE = ½ m 2 v

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

m = 0. 10 kg v = 8. 0 m/s KE = ½ m v 2 KE = ½ (0. 10) (8. 0)2 KE = ½ (0. 10) (64. 0) KE = 3. 2 J

Potential energy is the 10. __________ energy _______ stored as a result of position or shape ____________.

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.

The formula for GPE is: PE = m g h

m = 50 kg h = 10. 0 m g = 9. 8 m/s 2 PE = m g h PE = (50 kg) (9. 8 m/s 2) (10. 0 m) PE = 4000 J

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.