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?