Question

In an elastic collision of two billiard balls, which of the following quantities remain conserved during the short time of collision of the balls (i.e., when they are in contact).
(a) Kinetic energy . (b) Total linear momentum ?
Give reason for your answer in each case.

Answer 1

Total linear momentum of the system of two balls is always conserved. While balls are in contact. There may be deformaiton which means eleastic PE which came from part of KE Therefore, KE may not be conserved.