MCQ
A body projected vertically upwards with a velocity $u$ returns to the starting point in 4 seconds. If $g=10 m / sec$, the value of $u$ is
- A$5 m / sec$
- B$10 m / sec$
- C$15 m / sec$
- ✓$20 m / sec$
✓
Answer
Correct option: D.
$20 m / sec$
(d) Time of flight $T=\frac{2 u}{g}=4 \mathrm{sec} \Rightarrow u=20 \mathrm{~m\mathrm{s$
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