CENTRE OF MASS AND ROTATIONAL MOTION (ASSIGNMENT)
1. Two bodies of masses 0.5 kg and 1 kg are lying in XY plane at (-1,2) and (3,4) respectively. What are the co-ordinates of the centre of mass?
Answer: 5/3, 10/3
2. Three points masses of 1 kg, 2 kg and 3 kg lie a (1,2), (0,-1) and (2,-3) respectively. Calculate the co-ordinates of the centre of mass of the system.
Answer: 7/6, -3/2
3. Three identical spheres each of radius r, and mass m are placed touching each other on a horizontal floor. Locate the position of centre of mass of the system.
Answer: r, r/√3
4. Two particles of mass 2 kg and 1 kg are moving along the same line with speeds 2m/s and 5m/s respectively. What is the speed of the centre of mass of the system. if both the particles are moving
(a) in same direction
(b) in opposite direction?
Answer: 3m/s, 1/3 m/s in the direction of 1 kg
