If the body A does a work in 20 s and body B does the same work in 40 s then, what is the ratio of their power respectively?
2:1
Let the power developed by body A = PA and power developed by body B = PB
Given, time taken by A, tA=20 s and time taken by B, tB=40 s.
Power, P=Work doneTime taken
As work done is constant or same, power is inversely proportional to time taken.
⇒PAPB=tBtA=4020=21.
Hence, power ratio = 2:1.