BIO Deltoid Muscle A crossing guard holds a STOP sign at arm’s length, as shown in Figure 11-63. Her arm is horizontal, and we assume that the deltoid muscle is the only muscle supporting her arm The weight of her upper arm is W u = 18 N, the weight of her lower arm is W 1 = 11 N, the weight of her hand is W h = 4.0 N, and the weight of the sign is W s = 8.9 N. The location where each of these forces acts on the arm is indicated in the figure A force of magnitude f d is exerted on the humerus by the deltoid, and the shoulder joint exerts a force on the humerus with horizontal and vertical components given by f x and f y respectively. (a) Is the magnitude of f x greater than less than or equal to the magnitude of f x ? Explain. Find (b) f d , (c) f x and (d) f y (The weights in Figure 11-63 are drawn to scale; the unknown forces are to be determined. If a force is found to be negative, its direction is opposite to that shown )
BIO Deltoid Muscle A crossing guard holds a STOP sign at arm’s length, as shown in Figure 11-63. Her arm is horizontal, and we assume that the deltoid muscle is the only muscle supporting her arm The weight of her upper arm is W u = 18 N, the weight of her lower arm is W 1 = 11 N, the weight of her hand is W h = 4.0 N, and the weight of the sign is W s = 8.9 N. The location where each of these forces acts on the arm is indicated in the figure A force of magnitude f d is exerted on the humerus by the deltoid, and the shoulder joint exerts a force on the humerus with horizontal and vertical components given by f x and f y respectively. (a) Is the magnitude of f x greater than less than or equal to the magnitude of f x ? Explain. Find (b) f d , (c) f x and (d) f y (The weights in Figure 11-63 are drawn to scale; the unknown forces are to be determined. If a force is found to be negative, its direction is opposite to that shown )
BIO Deltoid Muscle A crossing guard holds a STOP sign at arm’s length, as shown in Figure 11-63. Her arm is horizontal, and we assume that the deltoid muscle is the only muscle supporting her arm The weight of her upper arm is Wu = 18 N, the weight of her lower arm is W1 = 11 N, the weight of her hand is Wh = 4.0 N, and the weight of the sign is Ws = 8.9 N. The location where each of these forces acts on the arm is indicated in the figure A force of magnitude fd is exerted on the humerus by the deltoid, and the shoulder joint exerts a force on the humerus with horizontal and vertical components given by fx and fy respectively. (a) Is the magnitude of fx greater than less than or equal to the magnitude offx? Explain. Find (b)fd, (c)fx and (d)fy (The weights in Figure 11-63 are drawn to scale; the unknown forces are to be determined. If a force is found to be negative, its direction is opposite to that shown )
A hiker, who weighs 659 N, is strolling through the woods and crosses a small horizontal bridge. The bridge is uniform, weighs 4280 N, and rests on two concrete supports, one on each end. He stops 1/5 of the way along the bridge. What is the magnitude of the force that a concrete support exerts on the bridge (a) at the near end and (b) at the far end?
Problem 8: Consider a rigid steel beam of length L = 11.5 m and mass mb = 412 kg resting on two supports, one at each end. A worker of mass mw = 78 kg sits on the beam at a distance x from support A. Refer to the figure, though note that it is not drawn to scale.
Part (a) When the worker sits at a distance x = 4.5 m from support A, calculate the force, in newtons, that support B must exert on the beam in order for it to remain at rest. Use g with three significant figures.
Part (b) The force exerted on the beam by support A is measured and found to be FA = 2180 N. At what distance x, in meters, from support A is the worker sitting now?
A man holds a 169-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force , which is applied perpendicular to the forearm. The forearm weighs 22.2 N and has a center of gravity as indicated. Find (a) the magnitude of and the (b) magnitude and (c) direction (as a positive angle counterclockwise from horizontal) of the force applied by the upper arm bone to the forearm at the elbow joint.
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.