Question

A 800N man is playing on a seesaw with son who has a weight of 200N. If the child is sitting 3 meters away, how far will the man have to sit to balance the seesaw?

Answer 1

The clockwise moment has to be equal to the anticlockwise moment in order for the seesaw to be balanced.

Moment=Force \times perpendicular \hspace0.05cm distance\hspace0.05cm from\hspace0.05cm the\hspace0.05cm centre.

$\therefore$ The moment of the man = the moment of the boy

force(man)= 800N \\ force(boy)= 200N\\ Perpendicular\hspace0.05cm dist.(man)= ?\\ Perpendicular\hspace0.05cmdist.(boy)= 3\hspace0.05cmmetres\\

F_{m}\times d_{m}=F_{b}\times d_{b}\\ 800\times d_{m}= 200\times 3\\ d_{m}= \frac{800}{(200\times 3)} metres \\ d_{m}= 1.33\hspace0.05cm metres

The man would have to sit 1.333 metres away