CP8 Forces doing Work

Question 1

List the three ways that the energy of a system can be changed

Answer 1

through work done by forces, in electrical equipment, in heating

Question 2

What is the formula for work done?

Answer 2

Workdone = force x distance moved in the direction of the force

Question 3

What is the unit for work done?

Answer 3

joules

Question 4

What does work done mean?

Answer 4

energy transferred

Question 5

What is the formula for gravitational potential energy?

Answer 5

change in gravitational potential energy = mass x gravitational field strength x height

Question 6

What is the formula for kinetic energy?

Answer 6

KE= 1/2 x mass x velocity x velocity

Question 7

Define power

Answer 7

the rate at which energy is transferred

Question 8

What is the equation for power?

Answer 8

power = workdone/time

Question 9

What is the unit for power?

Answer 9

watt, W

Question 10

What is one watt equivalent to?

Answer 10

1 joule per second

Question 11

What is the equation for efficiency?

Answer 11

efficiency = useful energy transferred by the device / total energy supplied to the device