Chapter 8, Problem 21P

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 60-lb plank rests on a frictionless roller at A, and the 20-lb triangular support BD. Both bodies are homogenous. The coefficients of static friction are 0.4 at B and 0.3 at D. Determine the largest force P that can be applied to the plank without initiating motion.

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 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 square-threaded screw 0f the C-clamp has a mean diameter of 8 mm and a pitch of 1.6 mm. The coefficient of static friction between the threads is 0.2. If the torque C=1.50Nm is used to tighten the clamp, determine (a) the clamping force; and (b) the torque required to loosen the clamp.

The drum has a weight of 110 lb and rests on the floor for which the coefficient of static friction is μs = 0.30. Assume the center of gravity of the drum is located at its center. Pt. A : If a = 3 ft and b = 4 ft, determine the smallest magnitude of the force P that will cause the drum to start sliding.   Pt. B: If a = 3 ft and b = 4 ft, determine the smallest magnitude of the force P that will cause the drum to start tipping. Pt. C : Based on the results in the previous two parts, the impending motion of the drum is....   Slipping or Tipping?

The truck has a mass of 1.25 Mg and a center of mass at G. Determine the greatest load it can pull if: (a) the truck has rear-wheel drive while the front wheels are free to roll. (b) the truck has four-wheel drive. The coefficient of static friction between the wheels and the ground is µs=0.5, and between the crate and the ground, it is us=0.4. Note: Rear-wheel drive means the rear wheels must slip and four-wheel drive all four wheels must slip. So in this problem, the wheels must be on the verge of slipping, max. friction force. 800 mm 600 mm F1.5 m--–1 m 10°

30° -2 pies-- 1.5 pies + 1.5 pies 1.5 pies + 1.5 pies Each box in the stack of four boxes weighs 3 lb. The stack is transported on the dolly weighing 38 lb. Determine the maximum force F that the woman exerts on the steering crank shown so that neither box will tip over or slip. The coefficient of static friction at all contact points is us = 0.5. Dolly wheels roll freely. Ignore your mass.

A. Determine the angle between the wedge and the concrete and the wedge and the floor. B. Calculate the coefficient of static friction between the concrete and floor.