1. A store employee raises an 8.72-kg case of cola at a constant velocity from the floor to a shelf 1.72m above the floor. Later, a customer lowers the case 1.05 m from the shelf to a cart at a constant velocity. Draw FBD and determine the work done on the case {a} by the employee as the case rises (b) by gravity as the case rises (c) by the customer as the case descends 2. A parent pulls a toboggan with three children at a constant velocity for 38 m along a horizontal snow- covered trail. The total mass of the children and the toboggan is 66 kg. The force the parent exerts is 53 N [18 above the horizontal]. (a) Draw an FBD ofthe toboggan, and determine the magnitude of the normal force and the coefficient of kinetic friction. (b) Determine the work done on the toboggan by kinetic friction. (c) List three forces, or components of forces, that do zero work on the tobogga n. (d) How much work does the parent do on the toboggan in pulling it the first 25 m? 3. A rope pulls a 200 kg sleigh (as shown in the figure} up a slope at incline angle 0 = 37, through distance d = 20 m. If the sleigh starts and ends at rest and the snowyr slope is so slippery that we take it to be frictionless, how much work is done by: a} the gravity? b) the Normal force? :3) the deer