A body is projected at an angle such that K.E. at the highest point is reduced to half the energy at point of projection. The angle of projection is :

Options

A. 30°
B. 75°
C. 45°
D. 60°

Answer

C

Explanation

We know that K.E. at highest point = `E cos^(2)theta` where E is initial energy.
`:. Ecos^(2)theta=1/2E`
`costheta=1/sqrt(2)implies theta=45^@`