1. Work and Energy

2. W=Fd Work is force that causes displacement. W is work in Joules
d is distance in meters
F is force in Newtons

3. By definition, work is only done when force is parallel to displacement. (So if you are standing holding a heavy box, by definition you are doing NO WORK!!!)
If there is an angle between force and distance, we can use a modified formula…
W=Fd(cosΘ)

4. Example 1:
How much work is done on a 10lb. vacuum cleaner pulled 3.0 meters across the floor, at a 30 degree angle above the horizontal?

5. Example 2:
How much work is done when you hold a 50lb bag of dog food?

6. Kinetic Energy KE = ½ mv2 Kinetic energy is energy in motion
KE is kinetic energy in joules
m is mass in kg
v is velocity in m/s

7. Example 3:
Which has more kinetic energy, a volley ball with a mass of 3kg moving at 3m/s OR a bowling ball with a mass of 5kg moving at 2m/s?

8. Example 4:
What is the kinetic energy of a tennis ball which has a mass of 2.45g and a velocity of 115miles per hour?

9. Example 5:
If a 7.00kg bowling ball had equal kinetic energy to the tennis ball in the previous problem, what would its velocity be?

10. Homework:
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