Question

How much work (in j) must be done to lift a stack of bricks, which has a mass of 400 kg, from the ground to a height of 3 m? (g = 10 m/s2)?

Answer 1

Given: Mass m = 400 Kg;   Height h = 3 m;     g = 10 m/s²

Required:  Work = ?

Formula: Work = Force x distance  F = ma    a = g    F = mg

W = fd

W = mgh

W = (400 Kg)(10 m/s²)( 3 m)

W = 12,000 Kg.m²/s²

W = 12,000 J