Question

A ball is thrown upwards from the top of tower 40m high with velocity 10m/s. Find the time when it strikes the ground?

Answer 1

Explanation:

here is your answer Friend

Answer 2

Answer:

u=+10m/s, a=−10m/s

2

ands=−40m

(at the point where stone strikes the ground)

substituting in s=ut+

2

1

​

at

2

, we have

−40=10t−5t

2

or 5t

2

−10t−40=0

or t

2

−2t−8=0

Solve this, we have t=4s and −2s. Taking the positive value t=4s.