Question

a stone is released from the top of the building of height 20m calculate (a) the total time to return to the surface of the earth (b) its final veocity just before toching the ground

Answer 1

a) v =u +GT
20 = 0+ 9.8*t
9.8t=20
t=20/9.8
t= 200/98
t= 2.04 seconds

Answer 2

Answer:

u = 0 m/s

v = ??

s = 20 m

s = ut +1/2*g*t^2

20= 0+1/2*10*t

t= 4 sec

b) v=u+at

v=0+10*4=40m/s