Having seen a big stone falling from the top of a tower Ravi pulled his friend Kiran away. The

stone hit Ravi slightly and he got hurt. But he was saved from a major accident.

(a)What made Ravi act in such a way.

(b)From the top of a tower 100 m in height, a ball is dropped and at the same time another ball

is projected vertically upwards from the ground with a velocity of 25 m/s.Find when and where

the two balls meet. Take g = 9.8 m/sec2.

Ans: (a) More observation, presence of mind & Concern (ii) In the first case h = ½gt2

(b) For the second case 100-h = 25 t - ½gt2 where h is the height at which the two stones meet.

i.e., 100-h = 25t- h; 25t = 100; or t= 100/25 = 4 sec. ; h=78.4m

100% users found this answer helpful.