A thin uniform plank of side length L is leaning on a tilted cart that makes an angle with the ground. A cylindrical log of radius R = L/2 is resting on the plank. The masses of the plank and log are identical and friction is absent everywhere. The system is in equilibrium. 45 L (a) [15 points] Show that o tan 1 (5-122) 24.7. (b) [5 points] Is this equilibrium stable? Hint: Are there torques acting on the log? What about the plank?