A ball is thrown vertically upward from the top of a 60 m building at 20 m s⁻¹. Taking g = 10 m s⁻², its speed on reaching the ground is:
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A ball is thrown vertically upward from the top of a 60 m building at 20 m s⁻¹. Taking g = 10 m s⁻², its speed on reaching the ground is:

G1 Physics · Accepted Answer

Using v² = u² + 2gH in magnitude form for the net fall of 60 m: v² = 20² + 2(10)(60) = 1600, so v = 40 m s⁻¹.