The 40-lb spool is suspended from the hanger GA and rests against a vertical wall. The center of gravity of the spool is at G and the weight of the hanger is negligible. The wire wound around the hub of the spool is extracted by pulling its end with the force P. If the coefficient of static friction between the spool and the wall is 0.25, determine the smallest P that will extract the wire.

The 3600-lb car with rear Wheel drive is attempting to tow the 4500-lb crate. The center of gravity of the car is at G, and the coefficients of static friction are 0.6 at B and 0.2 at C. Determine if the crate will slide.

The mass of the unbalanced disk is m, and its center of gravity is located at G. If the coefficient of static friction is 0.2 between the cylinder and the inclined surface, determine whether the cylinder can be at rest in the position shown. Note that the string AB is parallel to the incline.

The brake pads at C and D are pressed against the cylinder by the spring BF. The coefficient of static friction between each pad and the cylinder is 0.15. Find the smallest tension in the spring that would prevent the cylinder from rotating when the clockwise couple M=2200lbin. is applied. Neglect the weights of the members.

The 600-lb cable spool is placed on a frictionless spindle that has been driven into the ground. If the force required to start the spool rotating is F = 160 lb, determine the coefficient of friction between the ground and the spool. Neglect the diameter of the spindle compared to the diameter of the spool.

The two uniform sheets of plywood, each of length L and weight W, are propped as shown. If the coefficient of static friction is 0.5 at all three contact surfaces, determine whether the sheets will remain at rest.

The two homogeneous bars AB and BC are connected with a pin at B and placed between rough vertical walls. If the coefficient of static friction between each bar and the wall is 0.25, determine the largest angle 6 for which the assembly will remain at rest.

The blocks A and B of weights WA and WB are joined by a rope that passes over the fixed peg C. The coefficients of static friction are =0.2 between block A and the inclined plane, and =0.25 between the rope and the peg. Determine the range of Wb/WA for which the system will be in equilibrium.

The panel of weight W with its center of gravity at G is placed between vertical guides and released. Determine the largest height h for which the panel will not slide down due to binding at corners A and B. The coefficient of static friction between the panel and the guides is 0.5.