Problem 4-4 (page 138) Solution: 80(9.81)N is the effect of the cable Draw the free body diagram of the beam which supports the 80-kg load and is supported by the pin at A and a cable which wraps around the pulley at D. Explain the significance of each force on the diagram. Solution: 80(9.81)N is the effect of the cable (the weight of the object) on the beam. T is the effect of the cable on the beam. Ax and Ay are the effect of the pin Support on the beam.

Problem 4-8 (page 139) Solution: Draw the free-body diagram of the winch, which consists of a drum radius 4 in. It is pin-connected at it center C, and at its outer rim is a ratchet gear having a mean radius of 6 in. The pawl AB serves as a two-force member (short link) and holds the drum for rotating. Solution:

Problem 4-23 (page 155) Solution: The uniform rod AB has a weight of 15 lb. Determine the force in the cable when the rod is in the position shown. Solution:

Problem 4-32 (page 156) Solution: Determine the resultant normal force acting on each set of the wheels of the airplane. There is a set of wheels in the front, A, and a set of wheels under each wing, B. Both wings have total weight of 50 kip and center of gravity at Gw, the fuselage has a weight of 180 kip and center of gravity at Gf, and both engines(one on each side) have a weight 22 kip and center of gravity at Ge. Solution:

Problem 4-57 (page 172) Solution: The triangular plate is supported by a ball-and-socket joint at B and rollers at A and C. Determine the x, y, z components of each reaction at these supports due to the loading shown. Solution:

Problem 4-70 (page 174) Solution: Cable BC and DE can support a max. tension fo 700 lb before it breaks. Determine the greatest weight W that can be suspended from the end of the boom. Also, determine the x, y, z components of reaction at the ball-and-socket joint A. Solution:

Problem 4-70 (continued)

Problem 4-70 (continued)

Problem 4-78 (page 189) Solution: The car has a weight of 4000 lb and a center of gravity at G. If it pulls off the side of a road, determine the greatest angle of tilt, , it can have without slipping or tipping over. The coeffiecient of static friction between its wheels and the ground is 0.4. Solution:

Problem 4-85 (page 190) Solution: The two stone blocks have weights of Wa=600lb and Wb=500lb. Determine the smallest horizontal force P that must be applied to block A in order to move it. The coeffeicient of the static friction between the blocks is 0.3 and between the floor and each block is 0.4. Solution:

Problem 4-85 continued

Problem 4-110 (page 194) Solution: Determine the angle  at which the applied force P should act on the log so that the magnitude of P is as small as possible for pulling the log up the incline. What is the corresponding value of P? The log weighs W and the slope  is known. Express the answer in terms of the angle of kinetic friction,  = atan (). Solution:

Problem 4-110 (continued)