Motion In A Straight Line Ques 42
42. A stone released with zero velocity from the top of a tower, reaches the ground in $4$ $ sec$. The height of the tower is $(g=10 m / s^{2}) \quad$
[1995]
(a) $20 $ $m$
(b) $40 $ $m$
(c) $80 $ $m$
(d) $160 $ $m$
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Answer:
Correct Answer: 42.(c)
Solution:
- (c) Initial velocity $(u)=0$; Time $(t)=4 $ $sec$ and gravitational acceleration $(g)=10$ $ m / s^{2}$.
Height of tower
$h=u t+\frac{1}{2} g t^{2}=(0 \times 4)+\frac{1}{2} \times 10 \times(4)^{2} =80$ $ m$.
BETA
