Question

A car of mass 2000 kg is lifted up a distance of 30 m by a crane in 1 min. A second crane does the same job in 2 min. Do the cranes consume the same or different amounts of fuel ? What is the power supplied by each crane ? Neglect Power dissipation against friction.

Answer 1

t₁ = 1 min = 60 s, t₂ = 2 min = 120 s 

W = F_s = mgs = 5·88 × 10⁵ J 

As both cranes do same amount of work so both consume same amount of fuel.

∴ P₁ = 9800 W & P₂ = 4900 W.