Consider a crane moving in the x direction while the mass m moves in the z direction, as shown in Figure AP3.6. The trolley motor and the hoist motor are very powerful with respect to the mass of the trolley, the hoist wire, and the load m. Consider the input control variables as the distances D(t) and R(t). Also assume that (t) < 50°. Determine a linear model, and describe the state variable differential equation.