Answer:
The force per unit length is 
Explanation:
The current carrying by each wires = 2.85 A
The current in both wires flows in same direction.
The gap between the wires = 6.10 cm
Now we will use the below expression for the force per unit length. Moreover, before using the below formula we have to change the unit centimetre into meter. So, we just divide the centimetre with 100.

The answer is in the picture.
Here, ball is released... and it is in free fall means with zero initial velocity.
We know, s = ut + 1/2 at²
Here, s = 1000 m
u = 0
a = 10 m/s2
Substitute their values,
1000 = 0 + 1/2 * 10 * t²
2000 = 10 * t²
t² = 2000 /10
t = √200
t = 14.14 s
In short, Your Answer would be 14.14 seconds
Hope this helps!