Consider an object on which the net force is a resistive force proportional to the square of it's speed?
For example assume the resistive force acting on a speed skater is f = -kmv^2, where k is a constant and m is the skater's mass. The skater crosses the finish line of a straight-line race with speed v_0 and then slows down by coasting in his skates. show that the skater's speed at any time t after crossing the finish line is v(t) = v_0/(1+ktv_0).