PHYS 1080 Lecture Notes - Lecture 5: Circular Motion, Centripetal Force, Angular Acceleration
5 Dec 2016
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Uniform circular motion: a body moves in a circle at a uniform (constant) speed. The velocity is tangent to the circle. Period (t): time to travel circumference [s] Radians: unit of measure of angular" distance in theta direction. Units: radians/second w = 2pi/t = (2pi)(f) ac = v^2/r = w^2r. Relationship between v and w v= wr. So, a second expression for centripetal acceleration is: ac = v^2/r = (wr)^2/r. Centripetal force: force directed radially inward on an object moving in a circular path. Note: the source of the centripetal force could be gravity, tension, friction, etc. Note also that the centripetal force isn"t an extra force it will always have some clear physical cause sum of f = ma. c = m( v^2/r) Do not add ad contributing force in fbd. Centrifugal force radially outward from axis of rotation. It is a ctitious force, arising from observations from a non-inertial frame of reference.
