To test quality of tennis ball, u drop it on the floor from height 4m. It rebounds to height of 2m. If the ball is in contact with the floor for 12ms, what is avge. acclrtn during that contact?(g=9.8m/s2)Also is there any way we can use without applying the concept of collision or elasticity?

dear chilukuri

velocity of teniss when it just about to touch the ground =√2g*4

                                                                               =√8g   or -√8g j

velocity of teniss ball when it just about to leave the ground after collison =√2g*2

                                                                                                          =√4g   or  √4g j

avg acceleration   = change in velocity /total time

                           =(√4g j +√8g j)/12* 10^-3

                          =(√2 + 1)√g *10³/6        m/sec²

 ^{All the best.
 
Regards,
Askiitians Experts
Badiuddin}