At the point where the ball stops it has speed of 0 m/s. When it continues to fall in every meter it gets 9.8 m/s so you just put this :
9.8 m/s2 x 2.5 m = 24.5 m/s
Answer:
Jedge = 0.076A/cm^2
Explanation:
If you want to know what is Jedge is convenient to use an integral. The total density current is given by:
(1)
But also, we have that the total current is

where we have used that 5mm=5*10^{-3}m.
By replacing (1) we obtain:

hope this helps!!