Kinetic and potential energy stores

Question 1

What happens to the GPE stores of an object when it moves up or down?

Answer 1

• The GPE store increases when object moves up

- The GPE store decreases when object moves down

Question 2

Why does an object projected upwards have an increase in GPE?

Answer 2

• Work is done to overcome gravitational force

Question 3

Why is it easier to lift an object on the moon?

Answer 3

• Moon’s gravitation field strength 1/6 of earth’s

- Moon < Earth

Question 4

Formula for GPE:

Answer 4

GPE = mass X gravitational field strength X (change in) height
Ep (J) = m (kg) X g (N/kg) X h (m)

Question 5

What is the amount of energy that a kinetic energy store depends on?

Answer 5

• Mass and speed

Question 6

Formula for Kinetic energy:

Answer 6

Kinetic energy = 1/2 X mass X speed squared

Ek (J) = 1/2 X m (kg) X v^2 (m/s)

Question 7

What is an elastic potential energy store?

Answer 7

• Energy stored in an elastic object when work is done on object

Question 8

Formula for Elastic potential energy:

Answer 8

EPE = 1/2 X spring constant X extension^2

Ee (J) = 1/2 X k (N/m) X e^2 (m)