Question

A body is projected such that its kinetic energy at the top is 3/4 th ​ of its initial kinetic energy.What is the initial angle of projection of the projectile with the horizontal ?

Answer 1

As there is no acceleration in horizontal direction the velocity component will remain same as VcosƟ and at highest point vertical component will be zero. So total velocity at top will be VcosƟ
Kinetic energy at highest point will be= ½ m( VcosƟ)2
Initial kinetic energy will be =1/2mV2
At highest point
kE at highest =3/4 kE initial
1/2 m( VcosƟ)2=1/2mV2 *3/4
cosƟ=(3)12/2
Ɵ=30 degree

Answer 2

Answer:

Refer to the attachment for your answer.