One particle of mass 1 kg is moving along positive x-axis with velocity 3 m/s. Another particle of mass 2 kg is moving along y-axis with 6m/s. At time t = 0, 1 kg mass is at (3m, 0) and 2 kg at (0, 9m), x-y plane is the horizontal plane. (surface is smooth for question 47 and rough for question 48 and 49)
If both the particles have the same value of coefficient of friction `mu=0.2`. The centre of mass will stop at time t = ............. s

Options

A. 1.5
B. 4.5
C. `3.0`
D. `2.0`

Answer

C

Explanation

First particle will stop after time, `t_(1)=v_(L)/(mug) rArr 3/(0.2 times 10) 1.5s`
Second particle will stop after time
`t_(2) rArr v_(2)/(mug) rArr 6/(0.2 times 10) rArr 3.0s`
Hence, centre of mass will stop when both the particles will stop ie, after 3 seconds.