A particle is projected in air with an initial velocity u directed at an angle `theta` above horizontal. After time `t_(0)` the velocity of the particle is directed at angle `phi` above horizontal.

Options

A. At time `t_(0)` magnitude of verticle component of velocity of the particle is `u cos theta cot phi`
B. At time `t_(0)` magnitude of rate of change of speed of the particle is `g sin phi`
C. The radius of curvature of the trajectory at time `t_(0)` is `(u^(2) cos^(2)theta)/(g cos^(3) phi)`
D. The value of time `t_(0)` is `u cos theta (tan theta - tan phi)//g`.

Answer

B, C, D

Explanation

`a_(x) = 0`
`u_(x) = v_(x)`
`u cos theta = v cos phi` ….(i)
`a_(T) = g sin phi` … (ii)
`a_(C ) = g cos phi = (v^(2))/(r )` …(iii)