Mr. Verma (50kg) and Mr. Mathur (60kg) are sitting at the two extremes of a 4 m long boat (40 kg) standing still in water. To discuss a mechanics problem, they come to the middle of the boat. Neglecting frictioin with water how far does the boat move on the water during the process?

Explanation

`m_1=60, m_2=40kg, m_3=50kg`
Let A be the origin of the system. Initially Mr. Verma and Mr. Mathur are ast extreme positions of the boat

`:. Distnce o the centre of mass`
`(60xx4+40xx2+50xx4)/150`
=280/150=1.87` from A
when they come to the midpoint of boat, the CM lies at 2 m from A. Shift in CM=2-1.87=0.13m right
but as there is no exterN/Al force in longtudiN/Al dilrectioin C.M. would not hsift. so the boat mvoes 0.13 m or 13 cm towards right.