Question

A projectile is fired at $30^{\circ }$ with momentum $p$. Neglecting friction, the change in kinetic energy, when it returns back to the ground, will be

• A. zero
• B. 30%
• C. 60%
• D. 100%

Answer 1

Answer: (A)

The energy possessed by a body due to velocity $(v)$ is known as kinetic energy of the body. When a body is projected with velocity $v$ at an angle $\theta$ with the horizontal, then kinetic energy (KE) of projection
$=$ kinetic energy of returning.

Since, velocity of projection is equal to velocity of return.
Hence, change in kinetic energy is zero.