Question

A mother is helping her children, of unequal weight, to balance on a seesaw so that they will be able to make it tilt back and forth without the heavier child simply sinking to the ground. Given that her heavier child of weight W is sitting a distance L to the left of the pivot, at what distance L1 must she place her second child of weight w on the right side of the pivot to balance the seesaw?

Answer 1

Answer:

L₁ = W×L / w

Explanation:

The scenario is shown in the image below.

At the pivot point, the torque acting on this point must be zero so that there will be easy back and forth without the heavier child.

Torque created by lighter child + Torque created by the heavier child = 0

Thus,

According to the axis system, the heavier child is left to the pivot (origin), so,

W×(- L ) + w× L₁ = 0

So,

L₁ = W×L / w