Question

Two children of mass 20 kg and 30 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If the children are separated by a distance of 3 m, at what distance from the pivot point is the small child sitting in order to maintain the balance?

Answer 1

Step-by-step explanation:

Given

mass of first child
`m_1=20\ kg`

mass of second child
`m_2=30\ kg`

Distance between two children is
`d=3\ m`

Suppose light weight child is placed at a distance of x m from Pivot point

therefore

Torque due to heavy child
`T_1=m_2g* (3-x)`

Torque due to small child
`T_2=m_1g* x`

Net Torque about Pivot must be zero

Therefore
`T_1=T_2`

`30* g* (3-x)=20* g* x`

`9-3x=2x`

`9=5x`

`x=(9)/(5)`

`x=1.8\ m`