Q139 / 160 · WBJEE 2012 · Physics
A particle is projected from the ground with a kinetic energy $E$ at an angle of $60^{\circ}$ with the horizontal. Its kinetic energy at the highest point of its motion will be
- A$E / \sqrt{2}$
- B$E / 2$
- Correct answerC$E / 4$
- D$E / 8$
Solution
At ground, $E=\frac{1}{2} m u^{2}$
At highest point, $E^{\prime}=\frac{1}{2} m\left(u \cos 60^{\circ}\right)^{2}$
$$
E^{\prime}=\frac{E}{4}
$$
Hence, the correct answer is option: 'C'.