3. Consider the figure below. Two blocks are connected with solid strut attached to each other with frictionless pins. If coefficient of friction under each block is 0.25 and block B weighs 500 lb, find the minimum weight of A to prevent motion. 30 B/ 4. Consider the figure used in problem 3. Two blocks are connected with solid strut attached to each other with frictionless pins. If coefficient of friction under each block is 0.25 and block A weighs 400 N, find the minimum weight of B that is when motion is impending.