Moving House

Rule for Work
Work = Force X Displacement or W = F • s

(W in Joules) (F in Newtons) (s in meters)

Rule for Power
Power = Work ÷Time or P = W ÷ T

(P in Watts) (W in Joules) (t in seconds)

1. Work is done when a force moves an object or changes its direction. It is measured in
a. metersb. secondsc. secondsd. newtonse. Joules f. watts

2. Power is the rate at which is done.
a. forceb. momentumc. kinetic energyd. worke. potential energy

3. Power is measured in .
a. metersb. secondsc. secondsd. newtonse. Joules f. watts

4.Why are both energy and work measured in Joules?
a.because it takes energy to do work, so work is energy
b.because it is just an accident of the units and how it works out
c.because Joules is also used as a unit for force

All the answers to the following questions come from the set of answers below. Write the letter of the answer after the question.
a. 100 W b. 750 J c. 104 Wd. 1764 J e. 98000 J
f. 33 J g. 200000 W h. 60 J i. 504 W j. 400 J
k. 30 Jl. 100000 W m. 300 J n. 7000 Wo. 50 W

5.A ball with a weight of 30 Newtons is kicked 2 meters into the air. What work has been done?

6.A weightlifter lifts 2 weights of 200 Newtons each up to a height of 1 meter. What work has he done?

7.A furniture removalist lifts a box weighing 500 N into the back of a truck which is 1.5 meters above the ground. How much work has he done?

8.A 60 kilogram athlete runs up a 3 meter flight of stairs. What work has she done?

9.How much work does it take to push a 1 metric ton truck a distance of 10 meters?

10.If a person does 6000 Joules of work in one minute, what power has he?

11.A bulldozer does work at a rate of 12 MN every minute. How powerful is it?

12.A car with a forward force of 6 kN drives a distance of 1 kilometer in 1 minute. How much power does it have?

13.If the athlete in Question 8 ran up the stairs in 3.5 seconds. How powerful is she?

1. e
2. d
3. f
4. a
5. h
6. j
7. b
8. d
9. e
10. a
11. g
12. l
13. i