Chapter 8, Problem 40P

The spool of wire having a weight of 300 lb rests on the ground at B and against the wall at A. Determine the 3 ft normal force acting on the spool at A if P = 300 Ib. The coefficient of static friction between the spool and the ground at B is µ, = 0.35. The wall at A is smooth. ift B.

Determine the horizontal force P to start the 400-N wedge moving to the right. The angle of friction for all contact surfaces is o = 20°. WA = 2000 N WB = 400 N 15°

1. If the spring is compressed a distance 6 and the coefficient of static friction between the tapered stub S and the slider A is sA, determine the horizontal force P needed to move the slider forward.The stub is free to move without friction within the fixed collar C. The coefficient of static friction between A and surface B is µAB. Neglect the weights of the slider and stub. Given: 8 = 60 mm HsA = 0.5 HAB = = 0.4 N k = 300 e = 30 deg B

The drum has a weight of 100 lb and rests on the floor for wich the coefficient of static friction is Ms = 0.5 If a = 3 ft and b = 4 ft, determine the smallest magnitude od the force P that will cause impending motion of the drum.

4. The three bars have a weight of WA = 20 lb, WB = 40 lb, and We = 60 lb, respectively. If the coefficients of static friction at the surfaces of contact are as shown, determine the smallest horizontal force P needed to move block A CCB=0.5 BR 0.3 AHAD 0.2 D P

The brake is to be designed to be self locking, that is, it will not rotate when no load P is applied to it when the disk is subjected to a clockwise couple moment Mo. Determine the distance d of the lever that will allow this to happen. The coefficient of static friction at B is µs = 0.5. P -1.5 ft B Mo 1 ft 1.5 ft

The rope running over two fixed cylinders carries the 4-kg mass at one end. Determine the force P that must be applied to the other end to initiate motion. The coefficient of static friction between the rope and the cylinders is 0.15. 50 mm 150 mm 400 mm 4 kg O 64.1 N 63.1 N 65.1 N O 62.1 N

Determine the smallest force P needed to lift the 1000kg load. The coefficient of static friction between A and C and between B and D is μs=0.3, and between A and B μs’=0.4. Neglect the weight of each wedge.

The man has a mass, m. He plans to scale the vertical crevice using the method shown. If the coefficient of static friction between his shoes and the rock is μ₁ and between his backside and the rock is Hb, determine the smallest horizontal force his body must exert on the rocks in order to do this. m=45kg Us=0.30 Ub=0.35