1) Apply (-4?2) to compute the amount of work done in lifting a 100 lb weight a height of 10 ft assuming that this work is done against the constant force of gravity.
2) A cylindrical tank of radius 5 ft and height 10 ft is resting on the ground with its axis vertical. Use (answer from question 1) to compute the amount of work done in filling this tank with water pumped from ground level. (use p = 62.4 lb/ft^3 for the weight density of water).
3) Show by direct computation that the centriod of the triangle with vertices (0,0), (r,0), and (0,h)is the point(r/3,h/3). Verify that this point lies on the line from the vertex (0,0) to the midpoint of the opposite side of the triangle and two-thirds of the way from the vertex to that midpoint.