Answer: -17.66 m/s or 17.66 m/s downwards
Explanation:
The decribed situation is related to vertical motion and the main equation is:
(1)
Where:
is the final height of both stones
is the initial height of both stone
s
is the initial velocity of the stone
In the case of the first stone is
and for the second stone
is different from zero
is the time, which is the same for both stones
is the acceleration due to gravity
Having this clear, let's find
for the first stone:
(2)
(3)
Isolating
:
(4)
(5)
(6)
Now we have to use this time to find
:
(7)
Isolating
:
(8)
(9)
Finally:
(10) The negative sign indicates the direction of the initial velocity is vertically down