A stone is projected at angle 30 ° to the horizontal. The ratio of kinetic energy of the stone at point of projection to its kinetic energy at the highest point of flight will be :

Step-by-step solution

Let stone is projected with initial velocity v . Kinetic energy of the stone at point of projection is K E 1 = 1 2 m v 2 . Now, velocity of stone at maximum height is = v cos 30 ° , so kinetic energy at that point is K E 2 = 1 2 m v cos 30 ° 2 Hence, the ratio K E 1 K E 2 = 1 2 m v 2 1 2 m v cos 30 ° 2 = 4 3