Power

Definition

Power is the rate at which work is done or energy is transferred over time. It is measured in watts (W), where one watt equals one joule per second.

5 Must Know Facts For Your Next Test

1. Power ($P$) is mathematically defined as $P = \frac{W}{t}$, where $W$ is work and $t$ is time.
2. The SI unit of power is the watt (W).
3. In mechanical systems, power can also be calculated using $P = F \cdot v$, where $F$ is force and $v$ is velocity.
4. For electrical systems, power can be calculated as $P = V \cdot I$, where $V$ is voltage and $I$ is current.
5. Efficiency of a system can be determined by comparing the output power to the input power.

Review Questions

• What are the SI units for measuring power?
• How do you calculate power in a mechanical system using force and velocity?
• What formula would you use to calculate electrical power?

Related terms

Work:

Work is the transfer of energy that occurs when a force makes an object move; it is calculated as the product of force and displacement.

Energy:

Energy is the capacity to do work or produce change; it exists in various forms such as kinetic, potential, thermal, etc.

Watt:

A watt (W) is the SI unit of power equivalent to one joule per second.