# 1. Eight books, each 4.9 cm thick with mass 1.2 kg, lie flat on a table. How much work is required to stack them one on top of another?

1. Eight books, each 4.9 cm thick with mass 1.2 kg, lie flat on a table. How much work is required to stack them one on top of another?2. A 392 kg piano slides 3.5 m down a 25.8° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction (between the piano and the ramp) is 0.43.A) Calculate the force exerted by the man.B) Calculate the work done by the man on the piano.C) Calculate the work done by the friction force.D) Calculate the work done by the force of gravity.E) Calculate the net work done on the piano.3. A grocery cart with a mass of 17.6 kg is being pushed at constant speed along an aisle by the force Fp = 17 N which acts at an angle of 19.5° (down) from the horizontal. Find the work done by each of the forces (mg, FN, Fp, Ffric) on the cart if the aisle is 16.1 m long.