Question

A stone is thrown vertically upward with velocity 14.7m/s . calculate (a) the greatest height (b) time taken to reach the highest point?

Answer 1

it's solved by parabolic motion equations. for maximum height and time taken to reach

Answer 2

u = 14.7 ms when the stone goes up final velocity ( v ) = 0 , acc = g ( -10 )
time to reach the max height :-
v = u - gt
- 14.7 = - 10 * t
t = 1.47 sec
total time of flight = 2 ( t )
= 2 ( 1.47 ) => 2.945 sec
maximum height :-
s = u*t - 1/2( gt )
= (14.7 * 1.47) - 1/2 * 10 * (1.47)
= 21.609 - 10.8045
= 10.9945 m
velocity with which it strikes the ground :-
for this u = 0 , v = ? , a = g , s = 10.9945 m
by 3rd eq of motion :
v = u + 2gs
v = 2 * 10 * 10.9945
v = ( 219.89 )
v = 14.8280 m/s