Question

Two particles of masses 2 kg and 3 kg are at rest and are separated by 10 m. If they move towards each other under the mutual force of attraction, they would meet at _____

(a) 6 m from 4 kg body

(b) 6 m from 6 kg body

(c) 4 m from 4 kg body

(d) 5 m from 6 kg body

I got this question during an interview.

This is a very interesting question from System of Particles topic in chapter System of Particles and Rotational Motion of Physics – Class 11

Answer 1

The correct option is (a) 6 m from 4 kg body

For explanation: The two bodies would meet at their centre of mass.

Sum of masses = 2 + 3 = 5 kg

Let us consider the 2 kg body as a reference;

The centre of mass from the 2 kg body =(3 x 10) / 5

 = 6 m.