4.    A 3kg ball traveling with a speed of 4 m/s makes a head-on collision with a 2kg ball initially at rest. After the collision, the 3kg ball continue to move in the original direction with a speed of 1 m/s.
     

a.  (7 points)

What is the velocity of the 2kg ball after the collision? State direction with respect to the figure clearly.
 
 
 
 
 
 
 
 
 

b.  (8 points)

How much mechanical energy is lost during the collision?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

c. (10 points)

If the two balls make contact for 0.01s during the collision. Estimate the average force exerted by the 2kg ball on the 3kg ball. Also estimate the average force exerted by the 3 kg ball on the 2kg ball. State direction with respect to the figure clearly.