Work, power and efficiency - AQA

1

Which is a correct example of work being done?

2

What are the correct units for work?

3

How much work is done by a 10 N force pushing a box 4 m across the floor?

4

If a motor does 500 J of work to lift a 200 N weight, how high was the weight lifted?

5

Which of the following is a definition of power?

6

A hair dryer transforms 10,000 J of energy in 4 s. What is its power?

7

A 60 W lamp is left on for 20 s. How much energy has been transformed?

8

In an electric kettle, what energy is not wasted?

9

What is the percentage efficiency of Christmas lights that give out 10 W of light radiation for an electrical power input of 200 W?

10

How might a toy car be made more efficient?