280 kg piano slides 4.1 m down a 30 incline and is kept from accelerating by a man who is pushing back on it parallel to the incline (Fig. 6-36). The…

280 kg piano slides 4.1 m down a 30° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline (Fig. 6-36). The effective coefficient of kinetic friction is 0.40.