Question

A stone is let fall from the top of a tower 60 m
high and at the same time another is projected vertically
upwards with a velocity of 20 m/s. The two will meet
after
(a) 1 sec
(c) 2 sec
(b) 3 sec
(d) 4 sec​

Answer 1

Answer:

(c)2 sec

Explanation:

The stone falling has

velocity= acceleration due to gravity

=10 m/s(approx)

Stone thrown upward has

velocity=20m/s ..given

2(20)+2(10)=60

Answer 2

Here, s=60m

u=20m/s

therefore by using,

s=1/2gt²

60=1/2×9.8×t²

60×2/9.8=t²

600×2/98=t²

t=3.499

they meet after 3.499 I. e. 3.5 seconds