Kinematics Question 232
Question: A ball is dropped from top of a tower of 100m height. Simultaneously another ball was thrown upward from bottom of the tower with a speed of 50 m/s ( $ g=10m/s^{2}) $ . They will cross each other after [Or it’ssa JEE 2002]
Options:
A) $ 1s $
B) $ 2s $
C) $ 3s $
D) $ 4s $
Show Answer
Answer:
Correct Answer: B
Solution:
$ h _{1}=\frac{1}{2}gt^{2} $ , $ h _{2}=50t-\frac{1}{2}gt^{2} $
Given $ h _{1}+h _{2}=100m $
therefore $ 50t=100\Rightarrow t=2\ \sec $
