A sled with mass 12. 00 kg moves in a straight line on a frictionless, horizontal surface. At one point in its path, its speed is 4. 00 m/s; after it has traveled 2. 50 m beyond this point, its speed is 6. 00 m/s. Use the work–energy theorem to find the net force acting on the sled, assuming that this force is constant and that it acts in the direction of the sled’s motion