Question

A stone throne vertically upwards with initial velocity u reaches a height h before coming down. show that the time taken to go up is same as the time taken to come down.

Answer 1

When the stone is going up:
initial velocity= u
v=0
height=h
accl. due to gravity =-g. (as the stone is going up)


v=u+gt
0=u-gt
-u=-gt
u=gt
t=u/g


When the stone is coming down:

v=u
u=0
h=h
g=+g(stone coming down)

v=u+gt
u=0+gt
u=gt
t=u/g


height is given for creating confusion

hence proved...