Two particles A and B of equal mass have velocities as shown

Two particles A and B of equal mass have velocities as shown in the figure to the right. If the particles collide, circle the situation(s) shown 111 the figures below that represent possible velocities for the particles after impact. The velocities in all figures are shown to scale. [0.5 mark for each correct answer]

Solution

Since thy have equal masses they will exchange velocities both for horizontal and vertical component.

horizontal is head on collision so they will have horizontal velocity in opposite direction.