Question

A body is projected at an angle 6 with the vertical with kinetic energy KE. What is the kinetic energy of the particle at the highest point?

• A. KE cos²θ
• B. KE sin²θ
• C. KE/2
• D. KE tan²θ

Answer 1

Answer: (C)

KE/2

Answer 2

Let v be the velocity of projection then KE = 1/2 mv², but velocity of body at highest point is vx = v sin θ.

∴ kinetic energy of the body at the highest point is equal to

1/2 m(v sinθ)² = 1/2 mv² sin²θ = KE sin²θ

for θ = 45⁰

K.E._top = KE sin²45⁰ = KE/2.