After putting stuff through google and some calculators, I’d say the answer is C.
Answer:
a) 
b) 
Explanation:
Given:
mass of ball, 
initial speed of the ball, 
mass of the person, 
a)
Using the conservation of linear momentum:
When the person catches the ball, assuming that the person catches it with an impact without absorbing the shock.



b)
When the ball hits the person and bounces off with the velocity of
.
Using the conservation of linear momentum:

where:
final speed of the ball after collision
final speed of the person after collision
initial velocity of the person = 0
putting the respective values in the above eq.


Answer:
it may be because of the movement of the atoms. i believe that the heat of the warm water makes it move faster, thus making the object float due to upthrust, or air pressure
Non metals produce something called protons they are ions