**Power**

The rate at which work is done is power (P). Power is the rate at which energy is transferred, or transformed from one form into another.

Power is measured in . This unit is commonly referred to as the watt (W)

**Example 1:**

A crate with a mass of 5kg is carried up a hill that is 4m high in 10s. Calculate the required power needed to complete this task:

Using and ;

The applied force is to the weight of the crate;

Calculate the work done;

Calculate the power;

Energy changes also occur when an object changes velocity or height. This requires power.

**Example 2:**

A 350kg motorbike accelerates from rest to a velocity of 15 in 3.2s. Calculate the power required to achieve this velocity:

Using and

Calculate the power;

Often it is useful to convert power values into KW (divide W by 1000)