Answer:If the coefficient of kinetic friction (u) is 0.2, what ... The force of friction for a 7.5-kg object being pushed horizontally at a constant speed ... needed to start the box moving? ... An applied force of 21 N accelerates a 9.0-kg wagon at 2.0 m/s² along the ... 3N = p. 88.2 N. (u=0,034. 5. A sled of mass of 50.0 kg is pulled along a flat,