Question

11.
A stone is drop from the edge of a roof.
(a) How long does it take to fall 4.9 m?
(b) How fast does it move at the end of that fall?
(c) What will be its acceleration after 3 seconds?​

Answer 1

Explanation:

a. t=1 sec

b. v=9.8 m/s

c. 12.44 m/s

Answer 2

Answer:

h = 19.6 m

u = 0

h = u t + 1/2 g t * t

19.6   = 0 + 1/2 * 9.8 * t * t            as  g = 9.8 m/s/s

t = 2 sec.    it takes 2 sec.

acceleration is always the same : g = 9.8 m/sec

velocity / speed at t = 2 sec is  =  u + g  t  = 0 + 9.8 * 2 sec = 19.6 m/sec