Question

Two projectiles are projected simultaneously from the top and bottom of a vertical tower of height `h` at angles `45^(@)` and `60^(@)` above horizontal respectively.Body strike at the same point on ground at distance `20m` from the foot of the tower after same time.
The speed of projectile projected from the bottom is
A. `40m//s`
B. `20/sqrt3m//s`
C. `40sqrt3m//s`
D. `20/sqrt(sqrt(3))m//s`

Answer 1

Correct Answer - D
`R_(1)=(U cos theta)t=U/sqrt2sqrtsqrt3`
`U/sqrt(2)2sqrtsqrt3=20,U=(10sqrt2)/(root(4)(3)) U/V=1/sqrt2`