Question

a stone is thrown in a vertically upward direction with a velocity of 10m/s from the top of a tower of height of 100m FInd the time interwal required for the stone to pass through two points A and B at a distance of 40m and 75m below the top of the tower, assuming that the stone misses the tower and strikes the ground

Answer 1

I tried solving this but was unable

Answer 2

Given, initial velocity, u=5ms

−1

Final velocity, v=0

Since, u is upward & a is downward, it is a retarded motion.

∴a=−10ms

−2

Height attained by stone, s=?

Time take to attain height, t=?

(i) Using the relation, v

2

−u

2

=2as, we have

s=v

2

−u

2

/2a

=(0)

2

−(5)

2

/2×(−10)=1.25m

(ii) Using the relation, v=u+at

0=5+(−10)t or

t=5/10=0.5s

Hope it will help you