The direction of a projectile at a certain instant is inclined at an angle `prop` to the horizontal , after `t` second, it is inclined at an angle `beta`. Prove that the horizontal component of the velocity of the projectile is `("gt")/(tan prop - tan beta)`.

Options

A. `(g)/(tan alpha-tan beta)`
B. `(gf)/(tan alha-tan beta)`
C. `(r)/(g(tan alpha-tan beta)`
D. `(gt)/((tan alpha+tan beta))`

Answer

b

Explanation

`tan alpha=(v_(y))/u cos alpha)`
`tan beta=(u_(y)-gt)/(u cos beta)`
`tan alpha -tan beta=(gt)/(u cos beta)`
`u cos beta= u cos alpha`
or `u cos beta=(gt)/(tan alpha-tan beta)`