Given that:
Distance , s = 18.5 m
Velocity , v = 3.85 m/s
Time , t =?
Since,
Velocity = distance/time
or
Time= distance/velocity
time= 18.5/ 3.85
time= 4.8 s
So the time elapse between the release of the ball and the ball passing home plate is 4.8 seconds.
initially coin is at rest and then it drop for total time t = 1.5 s
so here the speed of the coin at which it will hit the floor is to be find

here we know that

a = 9.8 m/s^2
t = 1.5 s
now from above equation


so it will hit the floor with speed 14.7 m/s
football hemets have pads that are filled with air and thick foam so when they are hit the foam asorbs the hit and the air keeps the hard outer shell of the helmet from hiting the players head