PHED-2116EL Lecture Notes - Lecture 13: Friction, Gravitational Energy, Angular Velocity
14 Dec 2018
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Document Summary
For a varying force, the work done is the area under a force vs displacement curve. Positive vs negative work: positive work entails the displacement of an object in the direction of the applied force, can be thought of as a force doing work on an object, ex. Total work: total work performed is the sum of all work completed weight still lowers: w total=w1+w2. Work and muscles: when muscles produce tension resulting in the motion of body segments, they perform work on those segments, concentric contraction entails the shortening of a muscle as it pulls two bones closer together. Positive work is done: eccentric contractions entail the lengthening of a muscle as it attempts to pull two bones closer together. Negative work is done: positive work requires a greater caloric expenditure than the same amount of negative work, when muscles produce tension resulting in the motion of segments, they perform work on those segments.
