A uniform plank of a seesaw is 5 meter long and supported at its centre.a boy weighing 40kgf sits at a distance 1.5meter from one end of the seesaw.where must a girl weighing 25kgf sit on the other end of the seesaw so as to balance the boy.

Answer 1

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Each side is 2.5 m.The 40 kg boy is 1.5m from the end or 1m from the center.
40*1 = 25*x
x is the distance from the center to the girl.

Answer 2

if an ideal machine ma=vr=5. if the efficiency of a machine is 80% the how much 'e' does one have do put to raise the load of 100 n