Question

on a seesaw, two children of of masses 30 kg and 50 kg are setting one side of it at a distance 2m and 2.5 m respectively from its middle . where should a man of mass 75 kg sit to balance it . for 10 icse physics

Answer 1

Answer:

Let the two children be sitting on the left arm. They will produce an anti-clockwise moment due to their weights about the middle point.

Total Anti-clockwise moment = 30 kgf × 2 m + 50 kgf × 2.5 m

= 60 kgf m + 125 kgf m = 185 kgf m

To balance it, the man should sit on the right arm (to produce a clockwise moment). Let his distance from the middle be x m. Then

Clockwise moment = 74 kgf × x m = 74 x kgf m

By thr principle of moments,

Anti-clockwise moment = Clockwise moment

185 = 74 x

or x =

18574 m

= 2.5 m (on the other side).