A ball is thrown straight up at 20 m/s (g = 10 m/s², no air resistance). What maximum height does it reach?
Answer and explanation
Correct answer: D. 20 m
- Step 1: At the top v = 0, so 0 = 20² − 2·10·h. Step 2. h = 400/20 = 20. Answer: 20 m. Why not the others: 40 forgets the 2 in 2gh, 10 halves wrongly and 200 divides by 2 only.
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