Chapter 17, Problem 29P

The 120-kg block A is suspended from a rope that runs around the fixed pegs B and C. The coefficient of static friction between the pegs and the rope is 0.25. Determine the range of the force P for which the system is in equilibrium.

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 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 leather rein used to fasten the horse to the hitching rail weighs 3.5 oz per foot. The coefficient of static friction between the rail and the rein is 0.6. If a 34-lb force acting on the bridle is sufficient to restrain the horse, determine the smallest safe length L for the free end of the rein.

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.

Determine the distance to which the 90-kg painter can climb without causing the 4-m ladder to slip at its lower end A. The top of the 15-kg ladder has a small roller, and at the ground the coefficient of static friction is 0.25. The mass center of the painter is di rectly above her feet. Ana. s = 2.55m

4. The mine car and its contents have a total mass of 6000 kg and a centre of gravity at G. If the coefficient of static friction 10 kN between the wheels and the 0.9 m •G tracks is u = 0.4 when the wheels are locked, find the normal force acting on the front wheels at B and the rear 0.15 m 0.6 m - 1.5 m wheels at A when the brakes at both A and B are locked. Does the car move? [Ans. NA = 16.5 kN, Ng =42.3 kN, the car does not move] %3D lyp

For the given system, the cylinder of mass m is attached to a frictionless pulley. The chord attached to the 60.0 kg block runs through the fixed drum with coefficient of friction equal to 0.20. The coefficient of friction between the block and the incline is 0.15. Determine the range of mass m so that the system remains at rest. 60 kg u=0.20 H-0.15 20° m Solution guide: Consider Case 1: the motion is impending down the plane. o What are the forces acting on the 60 kg block? o What is the direction of friction force? o Calculate the tension force acting on the block. Is this the heavier tension or the weaker tension? Consider Case 2: the motion is impending up the plane. o What are the forces acting on the 60 kg block? o What is the direction of friction force this time? o Calculate the tension force acting on the block. Is this the heavier tension or the weaker tension? (Note: Please match your answer to the provided answer, Answer: 16.4348 kg Sm S 85.0868 kg

The man is trying to push the homogeneous 20-kg ladder AB up a wall by applying the horizontal force P. Determine the smallest value of Pthat would move the ladder. The coefficient of static friction between the ladder and both contact surfaces is 0.3. 1.5 m 2 m Note that h = 5 m