Exercise 2.7 Three identical SRS open-chain arms are grasping a common object, as shown in Figure 2.17. (a) Find the number of degrees of freedom of this system. (b) Suppose there are now a total of n such arms grasping the object. How many degrees of freedom does this system have? (c) Suppose the spherical wrist joint in each of the n arms is now replaced by spherical joint revolute joint Figure 2.17: Three cooperating SRS arms grasping a common object. a universal joint. How many degrees of freedom does this system have?