RST Biophysics Lecture 2 Forces theraby PDF
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Uploaded by FelicitousTranscendental
Al-Ryada University for Science and Technology
Prof. Ahmad Abdellatif
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This document provides lecture notes on biophysics, focusing on forces and vectors. It includes examples and diagrams to illustrate concepts. Topics covered include center of gravity, torque, levers, and skeletal muscles.
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FORCES Prof. Ahmad Abdellatif Vectors 2 Vector Components )(مركبات المتجه: 3 Center of gravity 4 𝒘𝒆𝒊𝒈𝒉𝒕 𝒘 = 𝒎𝒂𝒔𝒔 × 𝒈𝒓𝒂𝒗𝒊𝒕𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝒂𝒄𝒄𝒆𝒍𝒆𝒓𝒂𝒕𝒊𝒐𝒏 If your mass=70kg & g=9.8 m/s2 𝑦𝑜𝑢𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 = 70 × 9.8 =686N...
FORCES Prof. Ahmad Abdellatif Vectors 2 Vector Components )(مركبات المتجه: 3 Center of gravity 4 𝒘𝒆𝒊𝒈𝒉𝒕 𝒘 = 𝒎𝒂𝒔𝒔 × 𝒈𝒓𝒂𝒗𝒊𝒕𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝒂𝒄𝒄𝒆𝒍𝒆𝒓𝒂𝒕𝒊𝒐𝒏 If your mass=70kg & g=9.8 m/s2 𝑦𝑜𝑢𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 = 70 × 9.8 =686N 5 𝑇𝑜𝑟𝑞𝑢𝑒 = 𝑛𝑜𝑟𝑚𝑎𝑙 𝑜𝑟 𝑝𝑟𝑒𝑝𝑛𝑖𝑐𝑢𝑙𝑎𝑟 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 × 𝐹𝑜𝑟𝑐𝑒 𝑇 = 𝐹 sin 𝜃 × 𝑟 6 Ex No 1 What happens when the body is forced? 7 Cont Ex No 1 8 9 Actually, a person can withstand a much greater sideways force without losing balance by bending the torso in the direction opposite to the applied force. This shifts the center of gravity away from the pivot point A. increasing the restoring torque produced by the weight of the body. Stability against a toppling force is also increased by spreading the legs, 10 Skeletal Muscles The skeletal muscles producing skeletal movements consist of : Many thousands of parallel fibers wrapped in a flexible sheath that narrows at both ends into tendons. Some muscles end in two or three tendons( biceps and triceps). Each end of the muscle is attached to a different bone. In general, the two bones attached by muscles are free to move with respect to each other at the joints where they contact each other. Leonardo da Vinci 11 Levers A lever is a rigid bar free to rotate about a fixed point called the fulcrum. The position of the fulcrum is fixed so that it is not free to move with respect to the bar. Levers are used to lift loads in an advantageous way and to transfer movement from one point to another. 12 Crowbar wheelbarrow limb movements of animals 13 𝐹 × 𝑑2 = W × 𝑑1 14 The Elbow The two most important muscles producing elbow movement are the biceps and the triceps. The contraction of the triceps causes an extension, or opening, of the elbow. while contraction of the biceps closes the elbow. 15 Ex No 2 𝑭𝒐𝒓𝒄𝒆𝒔 = 𝟎 𝒊𝒏 𝒙 & 𝒚 𝒅𝒊𝒓𝒆𝒄𝒕𝒊𝒐𝒏 16 Cont Ex No 2 𝐹𝑚 sin 𝜃 𝑻𝒐𝒓𝒒𝒆 = 𝟎 𝒂𝒓𝒐𝒖𝒏𝒅 𝒂𝒏𝒚 𝒑𝒐𝒊𝒏𝒕 17 Cont Ex No 2 18 THANKS
