Question

A load of 220kg is vertically pulled up by a crane through a vertical height of 16m in 40s. Calculate 

(1) Force acting in the upward direction 

(2) Total work done 

(3) Horse power of the engine pulling the rope 

[Take g = 9.8ms^-2; 1 HP = 750w]

Answer 1

Mass m = 220 kg g = 9.8ms^-2 h= 16m t = 40s 

(1) Force F = mg 

= 220 x 9.8 = 2156N 

(2) Total work done = W = F x S 

W = 2156 x 16 = 3496J

(3) Horse power of engine = 3496/40J = 87.4w

= 3496/(40 x 750) = 1.15HP.