Equations

Question 1

Work done/energy transfered

Answer 1

W=F x D
Work done/Energy transfered= force x distance

Work done = joules ( J )
Force= newtons ( N )
Distance= metres ( m )

Question 2

Change in object’s gravitational potential energy store

Answer 2

Change in object’s gravitational potential energy store = weight x change of height
🔺= Delta means ‘change in’
🔺Ep = mg🔺h

Change in object’s gravitational potential energy store = jouls ( J )
Weight= newtons ( N )
Change in height = metres ( m )

Weight= mass x gravitational feild strenght
Weight= (N)
Mass=(Kg)
Gravitational feild strenght =(N/Kg)

Question 3

Kenetic energy

Answer 3

2
Kenetic energy = 1/2 x mass x speed

Kenetic energy= joules ( J )
Mass= (Kg)
Speed squared= metres per second (m/s)

                      2 Ek=1/2 x m x v

Question 4

Efficiency

Answer 4

Efficiency = useful output energy / total input energy x 100

Multiply by 100 to make it a percentage (%)

Question 5

Power

Answer 5

Power= Energy transfered / time taken
Power= watts (w)
Energy transfered= joules ( J )
Time taken= seconds (s)