man is holding a 3.6-kg sphere in his hand with the entire arm held horizontally as shown in the figure. tensile force in the deltoid muscle prevents the arm from rotating about the shoulder joint O; this force acts at the angle shown. Determine the force exerted by the deltoid muscle on the upper arm at A and the x- and y-components of the force reaction at the shoulder joint O. The mass of the upper anm is (m,-1.9 kg), the mass of the lower am is (m-1.1 kg), and the mass of the hand is (my-0.4 kg); all the corresponding weights act at the locations shown in the figure. Group A X-2 mm Group B XI4 mm Group C X=6 mm

man is holding a 3.6-kg sphere in his hand with the entire arm held horizontally as shown in the figure. tensile force in the deltoid muscle prevents the arm from rotating about the shoulder joint O; this force acts at the angle shown. Determine the force exerted by the deltoid muscle on the upper arm at A and the x- and y-components of the force reaction at the shoulder joint O. The mass of the upper anm is (m,-1.9 kg), the mass of the lower am is (m-1.1 kg), and the mass of the hand is (my-0.4 kg); all the corresponding weights act at the locations shown in the figure. Group A X-2 mm Group B XI4 mm Group C X=6 mm

Glencoe Physics: Principles and Problems, Student Edition

1st Edition

ISBN:9780078807213

Author:Paul W. Zitzewitz

Publisher:Paul W. Zitzewitz

Chapter8: Rotational Motion

Section: Chapter Questions

Problem 74A

See similar textbooks

Similar questions

If the biceps brachii, attaching to the radius 2.5 cm from the elbow joint, produces 250 Nof tension perpendicular to the bone, and the triceps brachii, attaching 3 cm away fromthe elbow joint, exerts 200 N of tension perpendicular to the bone, how much net torqueis present at the joint? Will there be flexion, extension, or no movement at the joint? Is thetorque concentric or eccentric?
A 35 N forearm (we are ignoring the hand for this problem) are held at a 45 deg angle to the vertically oriented humerus. The COM of the forearm is located at a distance of 15 cm from the joint center at the elbow, and the elbow flexor muscles have a 3 cm moment arm. How much force must be exerted by the elbow flexor muscles to maintain this position? Hide answer choices A A 35 N C 81.7 N 123.7 N D 371 N Fm 45° * --Wt₂
A 72.0 kg weightlifter doing armraises holds a 7.50 kg weight.Her arm pivots around theelbow joint, starting 40.0° belowthe horizontal (Fig.).Biometric measurements haveshown that, together, the forearmsand the hands account for 6.00%of a person’s weight. Since theupper arm is held vertically, thebiceps muscle always acts verticallyand is attached to the bonesof the forearm 5.50 cm from theelbow joint. The center of mass of this person’s forearm–hand combinationis 16.0 cm from the elbow joint, along the bones of the forearm,and she holds the weight 38.0 cm from her elbow joint. (a) Draw a freebodydiagram of the forearm. (b) What force does the biceps muscleexert on the forearm? (c) Find the magnitude and direction of the forcethat the elbow joint exerts on the forearm. (d) As the weightlifter raisesher arm toward a horizontal position, will the force in the biceps muscleincrease, decrease, or stay the same? Why?
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 =
DA man holds a 178-N ball in his hand, with the arm bone- 22. Upper - rlexor muscle forcarm horizontal (sce the draw- ing). He can support the ball in this position because of the flexor muscle force M, which is applied perpendicular to the forearm. The forearm weighs 22.0 N and has a center of gravity as indicated. Find (a) the magnitude of M and (b) the magnitude and direction of the force applied by the upper arm bone to the forearm at the elbow joint. Elbow cg joint '0.0890 m -0.330 m- 0.0510 m
The uniform plank ABC weighs 400 N. It is supported by a pin at A and a cable that runs aroundthe pulley D. Determine the tension in the cable and the components of the pin reaction at A. Note thatthe tension in the cable is constant
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a Wo = 195-N object. The spine and upper body are represented as a uniform horizontal rod of weight W₁ = 305 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0⁰. Back muscle R₂ T 12.0° 1T Rx Pivot a Wb Wo ..(a).Find the tension in the back muscle. 1.114 Enter a number. differs from the correct answer by more than 10%. Double check your calculations. kN…
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a Wo = 210–N object. The spine and upper body are represented as a uniform horizontal rod of weight Wb = 325 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a Wo = 210–N object. The spine and upper body are represented as a uniform horizontal rod of weight Wb = 325 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0°. a) find the tension on the back muscle. Answer: ____ kN b) find the compressional force In The spine. Answer: ____ kN
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a W 170-N object. The spine and upper body are represented as a uniform horizontal rod of weight W = 355 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0°. Back muscle Pivot = a R₂ T 12.0° Rx Wb Wo (i) (a) Find the tension in the back muscle. 1.114 Your response differs from the correct answer by more than 10%. Double check your calculations. kN (b)…
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a Wo = 215–N object. The spine and upper body are represented as a uniform horizontal rod of weight Wb = 330 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0°. (a) Find the tension in the back muscle. (b) Find the compressional force in the spine. (Enter the magnitude.)
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a person bending forward to lift a Wo = 195–N object. The spine and upper body are represented as a uniform horizontal rod of weight Wb = 290 N pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0°. In figure (a), a man bends his back forward to lift a set of weights. The hips are labeled as the pivot and the back muscle is also labeled to the right of the pivot. In figure (b), a…