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.

10) A femur bone of length 30 cm and diameter 2.5 cm is subjected to a compressive tress of 1.5 *10 8 N /m². Find the decrease in it's length if the young's modulus of bone is 1.5 * 10 10 N /m².

- 5. Two identical, uniform beams of length 3 m and weighing 260 N each are connected at one end by a frictionless hinge. A light horizontal crossbar, attached at the midpoints of the beams maintains an angle 50° between the beams. The beams are suspended from the ceiling by vertical wires so they form a V. See figure. (a) What force does the crossbar exert on each beam? (b) Is the crossbar under compression or tension, i.e. are the ends of the crossbar being pushed together or stretched farther apart? (c) What force (magnitude and direction) does the hinge exert on each beam? Crossbar Hinge

(25) A biomechanical model of the bones and biceps muscles of a person's arm supporting a mass m=2 kg is shown below. The weight of the forearm is 9 N. If the cross section of the tendon AB is 28 mm' what is the average normal stress in the tendon? 4f 290 mm r OS 150 mm 200 mm

The taho vendor carries a 1.5 m long light plank over his shoulder. At the ends of the plank are two buckets weighing 40 N and 60 N respectively. (a) Find the value of force F exerted by his shoulder. Neglect the weight of the plank. ( b) Where should he support the plank for it to be balanced horizontally

8₁ 02 9. The diagram of the leg shows the femur (1) and tibia (2). The quadriceps muscle (3) applies a force to the lower leg via a tendon (4) that is embedded with the kneecap (5). If the force applied by the muscle to the tendon is F 570 N, what is the force of the femur on the kneecap, if the leg is in equilibrium? A simplified model of the leg is shown next to the diagram. The leg bones are represented by two beams attached by a pin. The tendon is modelled by a rope and the kneecap acts like a pulley. The tendon above the kneecap makes an angle 8, = 38° with respect to the vertical, and the portion of the tendon below the kneecap makes an angle of 6₂ = 10° with respect to the vertical. Enter the x component, followed by the y component. Answer 1 of 2: Answer 2 of 2: Submit All Answers

(II) A 172-cm-tall person lies on a light (massless) board which is supported by two scales, one under the top of her head and one beneath the bottom of her feet (Fig. 9–64). The two scales read, respectively, 35.1 and 31.6 kg. What distance is the center of gravity of this person from the bottom of her feet? 35.1 31.6 KILOGRAMS KILOGRAMS FIGURE 9-64 Problem 24.

Two identical, uniform beams are symmetrically set up against each other (Fig. 9–87) on a floor with which they have a coefficient of fric- tion µs = 0.50. What is the minimum angle the beams can make with the floor and still not fall? FIGURE 9-87 Problem 71.

A 10 kg ladder has a length of 8 feet and leans on a vertical wall with an angle of 30 degree. Determine the force exerted by the tip of the ladder on the vertical wall and the force exerted by its foot on the horizontal ground. ( complete solution)