Particle A of mass m1 moving with velocity (3i^+j^) ms−1 collides with another particle B of mass m2 which is at rest initially. Let V1 and V2 be the velocities of particles A and B after collision respectively. If m1=2m2 and after collision V1=(i^+3j^) ms−1, the angle between V1 and V2 is:
a. 15∘
b. 60∘
c. −45∘
d. 105∘