// physics › Work & Power
Find mechanical power as the rate of doing work from work and time, or solve for work or time.
P = W / t
Power is how FAST you do work, not how much. Imagine carrying ten boxes upstairs. Whether you do it in one minute or one hour, the work is the same — but doing it in one minute takes much more power. Power is all about speed of getting work done.
Work is the total job done. Power is how quickly you finish it. Two students carry the same books up the same stairs; the one who runs up uses more power even though they both did the same work. Think of work as 'how much' and power as 'how fast'.
Sure. A motor does 500 joules of work in 10 seconds. Power = work ÷ time = 500 ÷ 10 = 50. So the power is 50 watts. A watt (W) just means 'one joule of work every second'. So 50 watts means it delivers 50 joules each second.
Exactly that watt! A 50-watt bulb uses 50 joules of energy every second. A 100-watt bulb uses energy twice as fast, which is why it is brighter and costs more to run. 1000 watts make one kilowatt (kW), the unit on your electricity bill.
Because it is about doing physical work — pushing, lifting, moving things. There is a separate kind called electrical power (for circuits and batteries) that has its own calculator. Same idea of 'how fast energy is used', just a different setting.
A sports car has a powerful engine — it does the work of speeding up very quickly. A strong kitchen blender, a fast lift in a tall building, a person sprinting upstairs: all high power. Doing the same job faster always needs more power.