A projectile is thrown in the upward direction making an angle of `60^(@)` with the horizontal direction with a velocity of 147 `ms^(-1)`. Then the time after which its inclination with the horizontal is `45^(@)`, is:

Options

A. 15s
B. 10.98s
C. 5.49s
D. 2.745s.

Answer

c

Explanation

Let the velocity of the projectile is v.
`v cos 45^(@)=u cos 60^(@) =u=147m//s`
Now, `v sin 45^(@)=u sin 60^(@)-gt`