-- 30N
-- the sum of all the forces
Baseball, javelin, and maybe the clock but not sure on that... Just say baseball and javelin
You have three known variables:
Acceleration -

Time -

Initial Velocity -

For the first part of your question:

For the second part of your question:

This still needs to be converted to m/h:
Answer:
The new force becomes 4 times the initial force.
Explanation:
The force of attraction or repulsion is given by the relation as follows :

Where
d is the distance between the interacting charges
F is inversely proportional to the distance between charges.
If the distance is halved, d'=(d/2), new force is given by :

So, the new force becomes 4 times the initial force.