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BIO When a gymnast performing on the rings executes the iron cross, he maintains the position at rest shown in Figure P10.85a. In this maneuver, the gymnast’s feet (not shown) are off the floor. The primary muscles involved in supporting this position are the latissimus dorsi (“lats”) and the pectoralis major (“pecs”). One of the rings exerts an upward fore
Figure P10.85
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Chapter 10 Solutions
Principles of Physics: A Calculus-Based Text
- Children playing pirates have suspended a uniform wooden plank with mass 15.0 kg and length 2.50 m as shown in Figure P14.27. What is the tension in each of the three ropes when Sophia, with a mass of 23.0 kg, is made to walk the plank and is 1.50 m from reaching the end of the plank? FIGURE P14.27arrow_forwardUnlike most of the other muscles in our bodies, the masseter muscle in the jaw, as illustrated in the figure, is attached relatively far from the joint, enabling very large forces to be exerted by the back teeth. This is shown in the figure below, where a person is biting down on a bullet placed between the back teeth. (FM= 210 N and rR = 4.1 cm.) (a) Using the information in the figure, calculate the magnitude of the force exerted by the teeth on the bullet. (b) Calculate magnitude of the force on the joint.arrow_forwardWhen a gymnast weighing 740 N executes the iron cross as in figure (a), the primary muscles involved in supporting this position are the latissimus dorsi ("lats") and the pectoralis major ("pecs"). The rings exert an upward force on the arms and support the weight of the gymnast. The force exerted by the shoulder joint on the arm is labeled F while the two muscles exert a total force F on the arm. Determine the magnitude of the force F Note that one ring supports half the weight of the gymnast, which is w 370 N as indicated in figure (b). Assume that the force F acts at an angle of 45° below the horizontal at a distance of 4.0 cm from the shoulder joint. In your estimate, take the distance from the shoulder joint to the hand to be L = 75 cm and ignore the weight of the arm. m kN Shoulder joint 4.0 cm- 45.00 Ed Bock/CORBISarrow_forward
- Scientists have studied how snakes grip and climb ropes. In one study, they found that an important characteristic of a rope is its “compliance”— that is, how easily the rope, while under tension, can be flexed. As shown how scientists measured a rope’s compliance by attaching it to two strings, each supporting an identical mass m. The strings contort the rope so that its middle section lies at angle θ. For θ = 30° and m = 100 g, what are the tensions T1 and T2 in the upper and middle parts of the rope?arrow_forwardA 50 N hand and forearm are held at a 35° angle to the vertically oriented humerus. The CG of the forearm and hand is located at a distance of 12.5 cm from the joint center at the elbow, and the elbow flexor muscles attach at an average distance of 2.5 cm from the joint center. (Assume that the muscles attach at an angle of 35° to the forearm bones.) How much force must be exerted by the forearm flexors to maintain this position?arrow_forwardWhen a gymnast performing on the rings executes the iron cross, he maintains the position at rest shown in figure (a). In this maneuver, the gymnast’s feet are off the floor. The primary muscles involved in supporting this position are the latissimus dorsi (“lats”) and the pectoralis major (“pecs”). One of the rings exerts an upward force Fh on a hand as shown in figure (b). The force Fs is exerted by the shoulder joint on the arm. The lats and pecs major muscles exert a total force Fm on the arm. Using the information in the figure, find the magnitude of the force Fm for an athlete of weight 750 N. Hint Fh = 750/2 N.arrow_forward
- A 50 N hand and forearm are held at a 35° angle to the vertically oriented humerus. The CG of the forearm and hand is located at a distance of 12.5 cm from the joint center at the elbow, and the elbow flexor muscles attach at an average distance of 2.5 cm from the joint center. (Assume that the muscles attach at an angle of 35° to the forearm bones.) How much force must the forearm flexors exert if a 50 N weight is held in the hand at a distance along the arm of 25 cm?arrow_forwardScientists have studied how snakes grip and climb ropes. In one study, they found that an important characteristic of a rope is its "compliance"--that is, how easily the rope, while under tension, can be flexed. (Figure 1) shows how scientists measured a rope's compliance by attaching it to two strings, each supporting an identical mass mm. The lower part of the rope is held under tension by a spring (not shown). The strings contort the rope so that its middle section lies at angle θ. For θ = 45∘ and mm = 400 g, what is the tension T2 in the middle part of the rope?arrow_forwardIf the allowable bending stress is 0 = 218 MPa, find the magnitude of the maximum internal bending moment M₂ that can be supported by the beam. The moment of inertia about the z axis is 402,238,667 mm4. 16 mm 240 mm V O 698 kN-m O 501 kN-m O 579 kN-m O 651 kN-m O 461 kN-m 30 mm 350 mmarrow_forward
- A person places his hand palm downward on a scale and pushes down on the scale until it reads 96.0 N. The triceps muscle is responsible for this arm extension force. Find the force exerted by the triceps muscle. The bottom of the triceps muscle is 2.50 cm to the left of the elbow joint, and the palm is pushing at approximately 29.0 cm to the right of the elbow joint. P 96.0 N 2.50 cm and Q = 29.0 cm. where P =arrow_forwardQ) A simplified model as shown in figure below of a planar robotic arm. You may assume that each segment has length 1.5 m, and the applied force is 250 N. 0, = 35° and 02 = 03 = 20°. Calculate the moment that the force, F, exerts about the point A. %3D F 02 Aarrow_forwardJohn is performing an isometric contraction of the quadriceps to hold a 500 N weight at an angle of 45° of knee extension (i.e., 45° below the horizontal). Assume the length of the lower leg is 42.5 cm. How much force must the quadriceps produce if the moment arm for the patellar tendon is 10 mm?arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning