Mr. Verma (50 kg) and Mr. Mathur (60 kg) 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 friction with water, how far does the boat move on the water during the process?
Taking the origin of the 1-D coordinate system to be at one extreme end of the boat where Mr. Mathur is sitting.
Mass of Mr. Mathur = m1 = 60 kg
Mass of Mr. Verma = m2 = 50 kg
Mass of the boat = m3 = 40 kg
Initial centre of mass of the system when both of them are sitting at extreme ends of the boat
Final centre of mass of the system when both of them are sitting at the centre of the boat = 2 m
Change in position of centre of mass of the boat = 2 – 1.87
= 0.13 m
= 13 cm
∴ The boat will move 13cm towards the side Mr. Verma was sitting.