Question

The uniform plank of a seesaw is 8 m long and is supported at the centre. A boy weighing 50 kgf sits at a distance of 2.5 m from the fulcrum. Where must another boy weighing 40 kgf sit, so as to balance the plank?

Answer 1

Let the distance of 40 kgf boy from fulcrum = x

50 kgf × 2.5 m = 40 kgf × x

∴ \[ x = \frac{50 \times 2.5}{40} \]

= 3.125 m