Question

A boy of mass 60 kg, and his sister of mass 49 kg,

play on a see-saw pivoted at its centre. If the boy sits
2.7 metres from the pivot of the see-saw, calculate
the distance from the other side of the pivot the girl
must sit to make the see-saw balanced.

Answer 1

3.18 meters

Step-by-step explanation:

Definition of Work

Work = force * displacement

`Work =fd`

In this case the force would be the weight.

Definition of Weight

Weight = mass * gravity

`W=mg`

If the see-saw is balanced the forces on each side must be equal.

`w_1*d_1=w_2*d_2`

`m_1*g*d_1=m_2*g*d_2`

`60*9.81*2.7=49*9.81*d_2`

`1589.22=49*9.81*d_2`

`1589.22=480.69d_2`

`(1589.22)/(480.6) =(480.6)/(480.6) d_2`

`3.18130187=d_2`