A particle of mass `m` is projected with velocity `u` at an angle `alpha` with horizontal. During the period when the particle descends from highest point to the position where
its velocity vector makes an angle `(alpha)/(2)` with horizontal. Work done by gravity force is

Options

A. `1/2 mu^(2)tan^(2)alpha`
B. `1/2 m^(2)tan^(2)alpha/2`
C. `1/2 mu^(2)cos^(2)alpha tan^(2)alpha/2`
D. `1/2mu^(2)cos^(2)alpha/2sin^(2)alpha`

Answer

C