A particle of mass m, kinetic energy K and momentum. p collides head on elastically with another particle of mass 2 m at rest. Match the following columns (after collision) and mark the correct option from the codes given below.A  B  C  D

p1 + p2 = p                                                                     …(i)Further,        K1 + K2=Kor        p122m+p224m=p22m or  2p12 + p22 = 2p2                …(ii)Solving Eqs. (i) and (ii), we get          p2=43p            and    p1=-p3, K1=K9 and K2=8K9Hence, A→r, B→p, C→q, D→s.