A ball is thrown vertically upward at 20 m/s. Taking g = 10 m/s2 and ignoring air resistance, what is the maximum height?
Answer and explanation
Correct answer: D. 20 m
- Step 1: At the top v = 0, so v^2 = u^2 - 2gh gives h = u^2 / 2g. Step 2. h = 400 / 20 = 20 m. Answer: 20 m. Why not the others: 40 m: That forgets to halve v squared over g. 10 m: That uses v^2/(4g). 2 m: That is the time to the top, not the height.
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