Physics Formula
Power Formula
Measures how quickly work is done or energy is transferred.
Formula Summary
Power
Measures how quickly work is done or energy is transferred.
- Category
- Physics
- Equation
- P = W ÷ t
- Calculator
- Use Power Calculator →
Equation
P = W ÷ t
Variables
- P = power
- W = work
- t = time
Units
- Power: Watt (W)
- Work/Energy: Joule (J)
- Time: seconds (s)
When To Use This Formula
Use this formula when calculating how quickly work is completed or how fast energy is transferred over time.
Rearranged Equations
- W = P × t
- t = W / P
How to Use This Formula
- Identify the known values from the problem statement.
- Convert all values into compatible units.
- Substitute the values into the equation and calculate the result.
- Check that the final answer has the correct unit and meaning.
Explanation
Power describes the rate at which work is completed or energy is transferred. A higher power value means the same amount of work is done in less time.
Worked Example
If 200 joules of work are completed in 10 seconds, the power is 200 ÷ 10 = 20 watts.
Common Mistakes
- Confusing power with total work or energy.
- Using incorrect time units.
- Forgetting that power measures a rate.
Applications
- Electrical and mechanical system analysis.
- Comparing machine performance.
- Energy efficiency calculations.