Motion in a Straight Line - Result Question 35
36. A ball is thrown vertically downward with a velocity of $20 m / s$ from the top of a tower. It hits the ground after some time with a velocity of $80 m / s$. The height of the tower is : $.g=10 m / s^{2}) \quad$ [2020]
(a) $340 m$
(b) $320 m$
(c) $300 m$
(d) $360 m$
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Answer:
Correct Answer: 36. (c)
Solution:
(c)
Using $v^{2}=u^{2}+2 g h$
Height, $h=\frac{v^{2}-u^{2}}{2 g}=\frac{(80)^{2}-(20)^{2}}{2 \times 10}$
$ =\frac{6400-400}{20}=300 m $
