(I) Calculate the mass m needed in order to suspend the leg shown in Fig. 9–47. Assume the leg (with cast) has a mass of 15.0 kg, and its CG is 35.0 cm from the hip joint; the cord holding the sling is 78.0 cm from the hip joint. •CG • Hip joint m FIGURE 9-47 Problem 2.

(I) Approximately what magnitude force, FM, must the extensor muscle in the upper arm exert on the lower arm to hold a 7.3-kg shot put (Fig. 9–71)? Assume the lower arm has a mass of 2.3 kg and its CG is 12.0 cm from the elbow-joint pivot. 2.5 cm -30.0 cm- Elbow joint FIGURE 9–71 Problem 32.

A uniform meter stick supported at the 25-cm mark is in equilibrium when a 1-kg rock is suspended at the 0-cm end (as shown in Fig. 9–37). Is the mass of the meter stick greater than, equal to, or less than the mass of the rock? Explain your reasoning. FIGURE 9-37 Question 8.

26. (III) Two wires run from the top of a pole 2.6 m tall that supports a volleyball net. The two wires are anchored to the ground 2.0 m apart, and each is 2.0 m from the pole (Fig. 9–66). The tension in each wire is 115 N. What is the tension in the net, assumed horizontal and attached at the top of the pole? \2.0 m -2.0 m FIGURE 9-66 Problem 26. 2.6 m 2.0 m-

34. (II) (a) Calculate the magnitude of the force, FM, required of the "deltoid" muscle to hold up the outstretched arm shown in Fig. 9–72. The total mass of the arm is 3.3 kg. (b) Calculate the magnitude of the force F; exerted by the shoulder joint on the upper arm and the angle (to the horizontal) at which it acts. EM 15° mg -12 cm -24 cm FIGURE 9-72 Problems 34 and 35.

Your doctor's scale has arms on which weights slide to counter your weight, Fig. 9–35. These weights are much lighter than you are. How does this work? Weights FIGURE 9-35 Question 4.

A uniform meter stick with a mass of 180 g is supported horizontally by two vertical strings, one at the 0-cm mark and the other at the 90-cm mark (Fig. 9–82). What is the tension in the string (a) at 0 cm? (b) at 90 cm? ib 20 30 40 50 60 70 90 loo FIGURE 9-82 Problem 63.

A 25-kg object is being lifted by two people pulling on the ends of a 1.15-mm-diameter nylon cord that goes over two 3.00-m-high poles 4.0 m apart, as shown in Fig. 9–86. How high above the floor will the object be when the cord breaks? 25 kg FIGURE 9-86 Problem 69.

(II) Find the tension in the two cords shown in Fig. 9–52. Neglect the mass of the cords, and assume that the angle 0 is 33° and the mass m is 190 kg. FIGURE 9-52 m Problem 12.

(I) Suppose the point of insertion of the biceps muscle intothe lower arm shown in Fig. 9–13a (Example 9–8) is 6.0 cminstead of 5.0 cm; how much mass could the person holdwith a muscle exertion of 450 N?