Consider the object shown in Fig. P4.73(a) with forces applied, where points A, B, and C...

Consider the object shown in Fig. P4.73(a) with forces applied, where points A, B, and C lie on the lines of action of these forces, respectively. If , show that these forces constitute a system of couples. Hint: Consider a point D whose location is arbitrary. Evaluate the moment of the three forces about point D and show that the result is independent of where D is located, as was done in Eqs. (4.13) and (4.14) on p. 233. Using Fig. P4.73(b), sketch a system of forces at points A, B, and C, including magnitudes, that will illustrate an example of the force system described in this problem.