Question

Particle is projected down at 10m/s from the top of a 40m high tower. Determine:
(a) Time taken by it in reaching ground?
(b) speed with which it hits the ground?​

Answer 1

Answer:

ANSWER

u=+10m/s, a=−10m/s2ands=−40m

(at the point where stone strikes the ground)

Substituting in s=ut+21at2, we have

−40=10t−5t2

or 5t2−10t−40=0

or t2−2t−8=0

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