PHYS 2001 Lecture : Chap 9 Notes
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5), but suppose an object"s speed around the circle changes. Angular displacement (cid:1)(cid:11) (cid:3) (cid:11)(cid:12) (cid:13) (cid:11)(cid:14) (cid:1)(cid:11) (cid:15) (cid:16): ccw rotations (cid:1)(cid:11) (cid:17) (cid:16): cw rotations. Point p traces out an arc of length (cid:20) (cid:3) (cid:21)(cid:11) where the angle (cid:2) is in radians! In radians, (cid:11) (cid:3) (cid:20)(cid:22)(cid:21) must be unitless! Count all revs don"t reset to (cid:1)(cid:11) (cid:3) (cid:16)! (cid:23)(cid:24)(cid:25)(cid:26)(cid:27) (cid:3) (cid:28)(cid:29)(cid:24)(cid:25)(cid:30)(cid:31) (cid:3) ! (cid:16)" : a space station consists of two donut-shaped living chambers, a and b, that have radii (cid:21)# (cid:3) (cid:28)(cid:24)% and (cid:21)& (cid:3) "(cid:28)! (cid:24)%, respectively. As the station rotates, an astronaut in chamber a is moved (cid:20)# (cid:3) (cid:23)((cid:28) m along a circular arc. It really, really helps to recall chapter 2!! Draw a dot on a cd (an ancient mp3 disc thingy ) and watch what happens. Note: , and 1 are positive when directed ccw. Units: , (cid:3) (cid:25)(cid:30)(cid:31)(cid:22)2 and 1 (cid:3) (cid:25)(cid:30)(cid:31)(cid:22)23.
