Power

POWER is the RATE at which energy is being TRANSFERRED or WORK is being done.

The equations for power can be written as:

UNITS:

• Power, denoted by P, is measured in Watts (W).
• Energy Transferred, denoted by E, is measured in Joules (J).
• Work Done, denoted by W, is measured in Joules (J).
• Time, denoted by t, is measured in Seconds (s).

One Watt is the power from an energy transfer of one Joule per second.

If a device is rated at 1 Watt, it means that it transfers energy at a rate of 1 Joule per second.

PRACTICAL APPLICATION

• Comparing two devices, like electric motors, is a good way to understand POWER.
• Let's say we have a 8W and 2W motor lifting a 1kg weight up a height of 1m:

• If both devices lift the same weight to the same height, the one that does it faster has a HIGHER POWER because it TRANSFERS energy at a FASTER rate.