A block of wood of mass `3M` is suspended by a string of length `(10)/(3) m`. A bullet of mass `M` hits it with a certain velocity and gets embedded in it. The block and the bullet swing to one side till the string makes `120^@` with the initial position. the velocity of the bullet is `(g=10 ms^(-2))`.

Options

A. `40/sqrt3 ms^(-1)`
B. `20ms^(-1)`
C. `30ms^(-1)`
D. `40ms^(-1)`

Answer

`(4)`

Explanation

`mu = (M + m) sqrt(2gl (1 -cos theta))`