Problem 3-57: A stationary truck is carrying a worker in its cockpit to replace street lights. At the instant sketched in Figure P3-57, all members are in the plane of the sketch, and the base A is rotating about a vertical axis at an angular velocity wi rad/s and an angular acceleration wi both with respect to ground. The main arm AB forms = = 0.25 0.15 rad/s, A 4.5 m W2, W2 B 2.5 m O 40 50 C g - = 0.20 an angle of 40 with respect to the vertical. The fore- arm BC is rotating at an angular velocity w2 rad/s and an angular acceleration w 0.35 rad/s, both with respect to the main arm AB, and about an axis that is orthogonal to the plane of the sketch, and forms an angle of 50 with respect to the vertical. The lengths of the main arm and the forearm are 4.5 m and 2.5 m, respectively. A worker, weighing 200 lb, is standing in the cockpit, and can be modeled as being at point C. Note that gravity acts. Find the velocity and acceleration of the worker at the instant shown.