Two particles A and B projected simultaneously from a point situated on a horizontal place. The particle A is projected vertically up with a velcity `v_(A)` while the particle B is projected up at an angle `30^(@)` with horizontal with velocity `v_(B)`. After 5s the particles were observed moving mutually perpendicular to each other. The velocity of projection of the particle `v_(A) and v_(B)` respectively are:

Options

A. `5ms^(-1),100 ma^(-1)`
B. `100ms^(-1),50 ma^(-1)`
C. `v_(A)` can have any value greater than `25ms^(-1),100ms^(-1)`
D. `20ms^(-1),25 ms^(-1)`

Answer

C

Explanation

`T_(A)=(2U)/g=5s , Ugt(5g)/2Ugt25 m//s`.
For any value `U gt 25` the projectile will move only in vertical direction.So `B` should move in horizontal direction at maximum height it is horizontal.
`T_(a)=(2U sin theta)/g=5=U/(2xx10) theta=30^(@)`
`U=100m//s`