Question

A person of 55 kg is holding a weight of 20 kg on his head. Calculate the work that is done against the gravitational force by it if it is to distance 20 meters (i) on a horizontal road, (ii) on such an inclined plane that has a horizontal tilt from 8 = sin '(1/5). Answer: (i) Zero, (ii) 3000 Joules. .

Answer 1

We know that,

Work done(W) = Force(F).Displacement(S) i.e., FScos∆

Hence, in first case,

W=FScos90

=0....(since cos90=0)

For second case,