Question

A ball is thrown vertically upwards with a velocity of 25 ms-1 from the top of a tower of height 30m. How
long will it travel before it hits ground -
(A)
6s
(B)
5s
(C)
4s
(D
12s
answer is 12sec but how explain...please​

Answer 1

Answer:

if we take g=10

the answer will be 6 sec not 12