A projectile can have the same range 'R' for two angles of projection. If `t_(1)` and `t_(2)` be the times of flight in the two cases, then product of the two times of flights is proportional to :

Options

A. `R^(2)`
B. `1/R^(2)`
C. `1/R`
D. `R`

Answer

D

Explanation

As range for `theta` and (90° - `theta`) is the same, the times of flight are given by
`t_(1)=(2usintheta)/g` and `t_(2)=(2ucostheta)/g`
`t_(1).t_(2)=(2u^(2)sin2theta)/g=(2R)/g` or `t_(1).tpropR`