Question

A stone thrown vertically upward 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

initial velocity=u
final velicity=0
acceleration=-9.8

since, v=u+at
therefore time taken = (v-u)/a
=-u/-9.8
=u/9.8

while decending, u=0
v= u while ascending
a=9.8
there fore time taken = (v-u)/a
=v/9.8
=u/9.8 since v=u while assending

therefore time is same