I'M STUCK! A cable used to lift heavy materials like steel I-beams must be strong enough to resist breaking even under a load of 1.3  106 N. For safety, the cable must support twice that load. (a) What cross-sectional area should the cable have if it's to be made of steel? m2(b) By how much will a 9.0-m length of this cable stretch when subject to the 1.3  106-N load? m

By how much does a 65.0kg mountain climber stretch her 0.800cm diameter nylon rope when she hangs 35.0m below a rock outcropping? (For nylon, Y=1.35109Pa. )

What Is Static Equilibrium? Problems 13 are grouped. 1. C A ball is attached to a strong, lightweight rod (Fig. P14.1). The rod is supported by a horizontal pin near the top. The ball is at rest. Is the ball in static equilibrium? If not, why not? If so, which type of equilibrium is itstable, unstable, or neutral? Hint: What would happen if you displaced the ball slightly? FIGURE P14.1

Alarge uniform cylindrical steel rod of density =7.8g/cm3 is 2.0 m long and has a diameter of 5.0 cm. the rod is fastened to a concrete floor with its long axis vertical.what is the normal stress in the rod at the cross-section located at (a)1.0 mfrom its lower end?(b)1.5 m from the lower end?

Two thin rods, one made of steel and the other of aluminium, are joined end to end. Each rod is 2.0m long and has cross-sectional area 9.1mm2 . If a 10,000N tensile force is applied at each end of the combination, find: (a) stress in each rod; (b) strain in each rod; and, (c) elongation of each rod.

A steel cable 2.00 m in length and with cross-sectional radius 0.350 mm is used to suspend from the ceiling a 10.0-kg model aircraft that is flying in a horizontal circle with an angular speed of 6.00 rad/s. What is the strain produced in the cable?

A copper wire is 1.0 m long and it diameter is 1.0 mm. if the wire hangs vertically how much weight must be added to its free end in order to stretch it 3.0mm?

At a museum, a 1300-kg model aircraft is hung from a lightweight beam of length 12.0 m that is free to pivot about its base and is supported by a massless cable (Fig. P14.38). Ignore the mass of the beam. a. What is the tension in the section of the cable between the beam and the wall? b. What are the horizontal and vertical forces that the pivot exerts on the beam? FIGURE P14.38 (a) From the free-body diagram, the angle that the string tension makes with the beam is = 55.0 + 18.0 = 73.0, and the perpendicular component of the string tension is FT sin73.0. Summing torques around the base of the rod gives (Eq. 14.2): =0:(12.0m)(1300kg)(9.81m/s2)cos55.0+FT(12.0m)sin73.0=0FT=(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0FT=7.65103N Figure P14.38ANS (b) Using force balance (Eq. 14.1): Fx=0:FHFTcos18.0=0FH=FTcos18.0=[(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0]cos18.0=7.27103NFy=0:FVFTsin18.0(1300kg)(9.81m/s2)=0 FV=FTsin18.0+(1300kg)gFV=[(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0]sin18.0+(1300kg)(9.81m/s2)FV=1.51104N

A rod of length 4.00 m with negligible mass is hinged to a wall. A rope attached to the end of the rod runs up to the wall at an angle of exactly 45, helping support the rod, while a sign of weight 10.0 N is hanging by two ropes attached to the bottom of the rod. The ropes make an angle of exactly 30 with the rod as shown in Figure P14.79. Another sign with a weight of 10.0 N is attached to the top of the rod with its center of mass at the midpoint of the rod. The entire system is in equilibrium. Find the magnitude of the tension in the rope above the rod that is also attached to the wall. FIGURE P14.79 Problems 79 and 80. N In Problem 79, find the magnitude of the vertical and horizontal components of the force that the hinge must exert on the rod to keep the system in equilibrium.

Suppose the weight of the drawbridge in Figure 9.34 is supported entirely by its hinges and the opposite shore, so that its cables are slack. (a) What fraction of the weight is supported by the opposite shore if the point of support is directly beneath the cable attachments? (b) What is the direction and magnitude of the force the hinges exert on the bridge under these circumstances? The mass of the bridge is 2500 kg.