Legend

 ac = centripetal acceleration v = velocity r = radius Fc = centripetal force m = mass

Circular Motion

 The focus of this chapter is on uniform circular motion, objects moving in a circle constant speed (number of revolutions per time does not change).  However, the velocity is always changing because the object is always changing direction as it travels.  since the velocity is always changing, that means the object is accelerating (even though its speed is constant).   This special type of acceleration is centripetal or radial acceleration, and is defined as: ac = v2/r the centripetal acceleration vector always points to the center of the circular path; the velocity points in the direction of movement (tangent to the circular path.  The result is that the acceleration and velocity vectors are perpendicular to each other: Circular motion also demonstrates that acceleration does not always have to be in the same direction or in the same plane as velocity. Recall Newton's 2nd law applies to circular motion, it says that if a body of mass m is accelerating, it must be experiencing a net force given by F = ma.  Which direction does the net force act?  Net force produces an acceleration in the direction of the net force; therefore, the force acts toward the center of the circular path. Fc = mac = mv2/r This is the net force required to centripetally accelerate an object in a circular path with a radius of r. Then why, when you release an object swung in a circular path, does it fly outward?  It takes a net force (the resultant of all forces) acting inward that keeps the object spinning in a circle; if you let go, the net force is no longer inward, so the object flies outward.
 Equilibrium Level Curves

 created by Will Kuo and Stan Watterson thinkquest participants  team 25844 ©1999 Eloquent Logic. All rights reserved.