Step 1: Given data and formula used
Let h be the height at which both balls collide.
Therefore, two balls will collide when :
h1=h2=h
Let the two balls collide t sec after the first ball is thrown.
Using, s=ut+12at2,
Step 2: Calculation of The height at which balls collide is
35t−12×10t2=35(t−3)−12×10(t−3)2
−5t2=−105−5t2−45+30t
30t=150
∴t=5 s
The height at which balls collide is,
h=35t−12×10t2
h=35×5−12×10×52
h=50 m
Correct answer :50