🔋college physics i – introduction review

Power

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

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.

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