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Power
Beginner
Rate of doing work.
P = W/tPower is the rate of doing work or transferring energy, P = W/t, in watts. A 100 W lamp uses 100 J every second.
Lifting 50 kg 3 m in 5 s needs about 294 W.
Don't confuse power with energy: kWh is energy.
In more detail
Power is the rate at which work is done or energy is transferred, P = W/t. The unit is the watt, equal to one joule per second.
Real-world uses
- Light bulbs and heaters are rated in watts to show how fast they use energy.
- Cars are rated in kilowatts to describe their performance.
- A kettle rated at 2 kW transfers 2000 joules of energy to the water every second.
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Frequently asked questions
What is the difference between energy and power?
Energy is the total amount, while power is how fast it is transferred.
How many watts is a horsepower?
About 746 watts.
How is power different from energy?
Energy is the total amount transferred, while power is how fast it is transferred. A lamp can use a lot of energy slowly or a little quickly.
Related topics in Work, Energy & Power
Roller coaster and loops · Energy loss to friction · General energy conservation · Instantaneous power · Units of power · Efficiency