Work is done when a force moves an object or changes its direction. It is measured in Joules.

Rule for Work

Work (joules) = Force (newtons) × Distance (metres)

Example to calculate Work

Question: A weightlifter raises weights of 2000 newtons from the floor to a height of 2 metres. How much work has been done?

Answer:

Work

= Force × Distance

= 2000 N × 2 m

= 4000 J (joules)

Power

Power is the rate at which work is done. Power is measured in Watts.

Rule for Power

Power (watts) =

Work (joules)

Time (seconds)

Example of calculating Power

Question: A weightlifter lifted 2000 newtons to a height of 2 metres. This was 4000 joules of work. What is the power output if this was done for 2 seconds?