A plumb bob is hanging by a thread from a bar attached to a rotating vertical shaft. The bob is linked to the shaft by a horizontal spring. The thread is made vertical by rotating the bob, spring and shaft at the appropriate speed. PART A-Analysing forces Draw the free-body diagram for the bob, and write down the force-acceleration equations in the radial (r) and vertical (2) directions when the system rotates. Side view when the bob is not rotating. The spring isn't stretched. Side view when the bob is rotating with a radius of rotation R. 1. What is the tension I in the string equal to in terms of (possibly) m, v. R, and g? 2. What is the force F. from the spring equal to in terms of (possibly) m. v, R, and g?