1. Work and Power Calculations
Even More Math??

2. Work Work occurs when a force causes an
object to move in the direction of the
force applied.

3. Work Formula Work = Force X Distance Work = Newtons X Meters
Units = Joules (J)

4. Work Calculation Example
A man applies a force of 5.0N to push a truck 10.0m down the street. How much work does he do?
W = F X D
W = 5.0 N X 10.0 M
W = 50.0 J

5. Work Problem 1
You push a 50.0N box 6.0m across the floor. How much work has been done?
W = F X D
W = 50.0N X 6.0m
W = 300.0J

6. Work Problem 2
Amy used 15.5N of force to push a lawn mower 2.5m. How much work does she do?
W = F X D
W = 15.5N X 2.5m
W = 38.8J

7. Work Problem 3
How much work is done by a person who uses a force of 65.4N to move a grocery cart 3.2m?
W = F X D
W = 65.4N X 3.2m
W = 209.3J

8. Work Calculation 4
Calculate the amount of work done when moving a 85.0N crate 15.0m.
W = F X D
W = 85.0N X 15.0m
W = J

9. Work Calculation 5
A basket of apples weighs 8.0N. If the basket is lifted 0.4m, how much work is being done?
W = F X D
W = 8.0N X 0.4m
W = 3.2J

10. Power
The rate at which work is done.

11. Power Formula Power = Work / Time Power = Joules / Seconds
Units = Watts (W)

12. Power Calculation Example
What is the power of a small motor that can do J of work in 10.0 seconds?
P = W / T
P = J / 10.0s
P = 250.0W

13. Power Problem 1
What is the power of an engine that can do J of work in 54.0 seconds?
P = W / T
P = J / 54.0s
P = 50.0 W

14. Power Calculation 2
What is the power of a motor that can do 18.2J of work in 2.4 seconds?
P = W / T
P = 18.2J / 2.4s P = 7.6W

15. Power Calculation 3
What is the power of a motor that can do J of work in 4.6 seconds?
P = W / T
P = J / 4.6s P = 271.7W