question_answer 39)

                  Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed V as shown in Fig.                 If the collision is elastic, which of the following (Fig.) is a possible result after collision?                                

Answer:

                  (b) Initial linear momentum = mV                 Initial \[KE=\frac{1}{2}\,m{{V}^{2}}\]                 Since collision is elastic, so linear momentum and K.E. after collision will also be \[mV\]\[mV\] and \[\frac{1}{2}\,m{{V}^{2}}\].