A particle A of mass 0.5kg is dropped from rest from a height of 8m above ground level.
At the same time a particle of mass 0.2kg is projected vertically upwards with a velocity
of 8m/s from the ground so that it collides and coalesces with A. find
a. The height at which they collide,
b. Their velocities just before impact,
c. Their common velocity after collision,
