A body is moving with a velocity v , breaks up into two equal parts. One of the part retraces back with velocity v . Then the velocity of the other part is

Options

A. v in forward direction
B. 3v in forward direction
C. v in backward direction
D. 3v in backward direction

Answer

B

Explanation

Let the initial mass of body = m
Initial linear momentum `= mv " "` …(i)
When it breaks into equal masses then one of the fragment retrace back with same velocity
`therefore` Final linear momentum `= (m)/(2)(-v)+(m)/(2)(v_(2)) " "` …(ii)
By the conservation of linear momentum
`rArr mv=(-mv)/(2)+(mv_(2))/(2)rArr v_(2)=3v`
i.e. other fragment moves with velocity 3v in forward direction