Two balls are projected simultaneously with the same speed from the top of a tower, one vertically upward and the other vertically downward. If the first ball strikes the ground with speed 20 m s⁻¹, the speed of the second ball on striking the ground is:
Options

Question

Two balls are projected simultaneously with the same speed from the top of a tower, one vertically upward and the other vertically downward. If the first ball strikes the ground with speed 20 m s⁻¹, the speed of the second ball on striking the ground is:

Options

G1 Physics · Accepted Answer

Both balls start from the same height with equal speed magnitude. By energy conservation, impact speed satisfies v²=u²+2gH, independent of initial direction. Therefore both strike with the same speed 20 m s⁻¹. Hence option B.