a projectile is fired from the surface of the earth with a velocity of `5ms^(-1)` and angle `theta` with the horizontal. Another projectile fired from another planet with a velocity of `3ms^(-1)` at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth.The value of the acceleration due to gravity on the planet is in `ms^(-2)` is given `(g=9.8 ms^(-2))`

Options

A. ` 3.5`
B. `5. 9`
C. ` 16 ,3`
D. ` 110.8`

Answer

A

Explanation

` y = x tan theta - (gt^2)/( 2 u^2 cos^2 theta)` ,
For equal trajectories for same angle of projection ` g/u^2 = cosntant rArr ( 9. 8)/5^2 = g'/3^2`
` g' = (9.8 xx 9) /(25) = 3 . 52 8 m//s^2 = 3.5 m//s^2`.