a stone is dtropped from the top of 40m heigh calculate its speed after 2 seconds .Also find the speed ith the stone strikes the ground.

Answer 1

Let V be the velocity (positive downwards) and Y be the distance the stone has fallen (also positive downwards).

V = g t
g is the acceleration of gravity, which is 9.8 m/s^2

When it strikes the ground,
Y = 40 = (1/2) g t^2

t = sqrt (2 Y/g)= 2.857 s
V = sqrt (2 g Y) = g * t = 28 m/s

Answer 2

200

Answer 3

Actually it is wrong....
S(distance)=40m
Speed= distance/time
i.e 40/2=20m/s.