A sled with m 7.80 kg moves in a straight line on a frictionless horizontal surface?

At one point in its path, its speed is 4.40 m/s; after it has traveled a distance 2.80 m beyond this point, its speed is 6.10 m/s.Find the force acting on the sled, uming that this force is constant and that it acts in the direction of the sled's motion.