Aparticle is constrained to move along a straight line through o.
it starts initially at d, which is a fixed distance from o in the positive direction& moves at a constant velocity of 4ms^-1 for 15 sec. until; it is 100m from o for a furhter 25 sec, after which it travels in the opposite direction for 20 sec.
the total distance is 180m.

how far from o does the particle stop?
how do i draw a velocity–time graph?
and what is the final displacement of the particle from its initial position?