Question

A man carries a load of 50 kg through a height of 40m in 25 sec then what is mass

Answer 1

Take mass of man as 'M'.

Assuming all energy is used to do work, use G.P.E = mgh.

Potential energy = (M+50) x 9.8 x 40

So G.P.E = 392M +19600

Other equation; Power = W/t

P = (392M + 19600)/25

so,

1568 x 25 = 392M + 19600

392M = 39200 - 19600

Mass 'M' = 19600/392 = 50Kg.

Answer 2

Since we know that W.D. = Energy
According to the eq. mgh
= (m +50) × 10 × 40
= 400m + 2000 Joule