The question asks for the kinetic energy (or ratio of kinetic energies) of a projectile at a specific point in its trajectory, typically the highest point, using the fact that only the horizontal velocity component remains.
A particle ($\mathrm { m } = 1 \mathrm {~kg}$) slides down a frictionless track (AOC) starting from rest at a point $A$ (height 2 m). After reaching $C$, the particle continues to move freely in air as a projectile. When it reaching its highest point P (height 1 m), the kinetic energy of the particle (in J) is: (Figure drawn is schematic and not to scale; take $g = 10 \mathrm {~ms} ^ { - 2 }$) $\_\_\_\_$.
A ball is projected with kinetic energy $E$, at an angle of $60 ^ { \circ }$ to the horizontal. The kinetic energy of this ball at the highest point of its flight will become : (1) Zero (2) $\frac { E } { 2 }$ (3) $\frac { E } { 4 }$ (4) $E$