P4-7. Determine the force P needed to cause impending motion of the block. W = 200 N Fim-

Identify the zero force members (if any) in the trus P 4 m -3m

P4-4. Determine the friction force at the surface of contact. 500 N W = 200 N H = 02

3-21. The 10-lb weight is supported by the cord AC and roller and by the spring. If the spring has an unstretched length of 8 in., and the weight is in equilibrium when d = 4 in , determine the stiffness k of the spring. Problems 3-20/21 A 12 in. B

*3-16. Determine the stretch of each spring for equilibrium of the 20-kg cylinder. Problem 3-16 Ja KAD=400 N/m KAB = 300 N/m KAC = 200 N/m 3 m 4 m 3 m

3-23. Determine the unstretched length of spring AC if a force P 80 lb causes the angle 6 60° for equilibrium. Cord AB is 2 ft long. Take k 50 lb/ft. 2 ft 2 ft C B

4-44. The tongs are used to lift the 150-kg crate, whose center of mass is at G. Determine the least coefficient of static friction at the pivot blocks so that the crate can be lifted. 275 mm 500 mm 500 mm 300 mm

*4-48. The pipe of weight Wis to be pulled up the inclined plane of slope a using a force P. If Pacts at an angle d, show that for slipping P = W sin(a + 0)/cos(6 - 6), where e is the angle of static triction; 8 = tan '-

Based on Problem 5-87 from the textbook. Both pulleys are fixed to the shaft and as the shaft turns with constant angular velocity, the power of pulley A is tramsitted to pulley B. Determine the horizontal tension T in the belt on pulley B and the x, y, z components of reaciotn at the journal bearing C and thrust bearing D. The bearings are in proper alignment and exrt only force reactions on the shaft. F₁ = 70 N F2=80 N Unique Values for F 300 mm F3 = 40 N 8= 44 44° 250 mm 200 mm F₁ F2 80 mm A 150 mm B

4-69. The pipe assembly is secured on the wall by the two brackets. If the frictional force of both brackets can resist a maximum moment of 150 lb-ft, determine the largest weight of the flowerpot that can be supported by the assembly. Problems 4-68/69 O 2 60° 4 ft 4 ft 3 ft 30° 3 ft B