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:
arrangement 2
Explanation:
arrangement 1's spring would broke idek
<span>Water in the oceans may become fresh water available to humans through the processes of evaporation, condensation and precipitation.
In these processes, water is heated to a very high temperature until it evaporates in order to kill the germs and remove the salts which remains after water evaporation. The next step in condensing the water vapor (which is now fresh) and precipitating this vapor to be used by humans.</span>