From the top of a tower of height `100 m` a `10 gm` block is dropped freely and a `6 gm` bullet is fired vertically upwards from the foot of the tower with velocity `100 ms^(-1)` simultaneously. They collide and stick together. The common velocity after collision is `(g = 10 ms^(-2))`.

Options

A. `27.5 ms^(-1)`
B. `150 ms^(-1)`
C. `40 ms^(-1)`
D. `100 ms^(-1)`

Answer

A

Explanation

time, `t = (h)/(u)`
For freely falling body : `u_(1) = g t`
For upward projected body, `u_(2) = u - g t`
`-m_(1)u_(1) + m_(2)u_(2) = (m_(1) + m_(2))v`.