For a given velocity, a projectile has the same range `R` for two angles of rpojection if `t_(1)` and `t_(2)` are the times of flight in the two cases then

Options

A. `t_(1)t_(2)propR`
B. `t_(1)t_(2)propR^(2)`
C. `t_(1)t_(2)prop1/(R^(2))`
D. `t_(1)t_(2)prop1/R`

Explanation

(a) `t_(1)=(2usin alpha)/g`
`t_(2)=(2u sin (90^(@)-alpha))/g`
So, `t_(1)xxt_(2)=2 (u^(2))/(g^(2)) sin 2alpha`
or `t_(1)xxt_(2)=(2R)/g` ( `:'R=(u^(2) sin 2alpha)/g`)
`t_(1)xxt_(2) propR`