(1) Suppose you lift a stone that has a mass of 5.1 kilograms off the floor onto a shelf that is 2 meters high. How much work have you done? Joules (2) Suppose you lift a laptop that weighs 3.6 pounds off the floor onto a shelf that is 3 feet high. How much work have you done? foot-pounds (3) The force on a particle is described by 7a+2 pounds at a point a feet along the z-axis. Find the work done in moving the particle from the origin to z = 2. foot-pounds