Particles A moves along the line with constant velocity
of magnitude
and directed parallel to the positive x-axis. Particle
starts at the origin with zero speed and constant acceleration a (of magnitude
) at the same instant that the particle
passes The y-axis. The angle
between
and y-axis that would result in a collision between these two particles should have a value equal
.

If is the time of collision, then for particle
and for particle ,
i.e..,
on substituting and simplifying we get.