Question

a boy weighing 20kg is sitting at one end of see saw at distance of 1.2m from the centre.where should a man weighing 60kg sit on see saw,so that it stands balanced ?

Answer 1

I think.............The man should sit on nearly 30 cm from the centre.

Answer 2

Let man sit at a distance of a m from the centre
If the see saw stands balanced,
See saw is in equilibrium
So, total moment of clockwise force = total moment of anticlockwise force
or, 1.2xgx20 = 60xgxa
or, a = 1.2x20/60 = 0.4

So, man should sit at a distance of 0.4m (40 cm) from the middle of the see saw on the opposite end of the boy.