A block and tackle having velocity ratio of 5 is used to raise load of 400N through a height of 10m.If the work done by friction is 1000j.calculate the work done by the effort

Answer 1

If there were no friction the work required is m g h = 400 *10
= 4,000 Joules
if you burn off 1,000 Joules as friction, then you need 5,000 Joules.

It does not matter what the mechanical advantage is, less force needs bigger distance pulled but same old work = force * distance.

Answer 2

V.R =5, Load= 400N, h=10m, workdone by friction=1000J
Work output(workdone by the load)=400×10=4000J
Work input= Work Output + Workdone by friction
4000J + 1000J= 5000J