The question just basically explained what happens
Answer:

Explanation:
According to the Coulomb's law, the magnitude of the electrostatic force between two static point charges
and
, separated by a distance
, is given by

where k is the Coulomb's constant.
Initially,

The negative sign is taken with force F because the force is attractive.
Therefore, the initial electrostatic force between the charges is given by

Now, the objects are then brought into contact, so the net charge is shared equally, and then they are returned to their initial positions.
The force is now repulsive, therefore, 
The new charges on the two objects are

The new force is given by

Using (1),



Using (1),
When
,

When
,

Since, 
Therefore, 
Answer:
The velocity of the man is 0.144 m/s
Explanation:
This is a case of conservation of momentum.
The momentum of the moving ball before it was caught must equal the momentum of the man and the ball after he catches the ball.
Mass of ball = 0.65 kg
Mass of the man = 54 kg
Velocity of the ball = 12.1 m/s
Before collision, momentum of the ball = mass x velocity
= 0.65 x 12.1 = 7.865 kg-m/s
After collision the momentum of the man and ball system is
(0.65 + 54)Vf = 54.65Vf
Where Vf is their final common velocity.
Equating the initial and final momentum,
7.865 = 54.65Vf
Vf = 7.865/54.65 = 0.144 m/s