science

=**Definition**= 1.centripetal force
 * 1) toc
 * 2) centripetal acceleration
 * 3) Rotation-object turns the internal axis.
 * 4) Revolution- object turns around the external axis
 * 5) linear speed-distance\time

centripetal force
Whenever an object moves in a circular path we know the object is accelerating because the velocity is constantly changing direction. All accelerations are caused by a net force acting on an object. In the case of an object moving in a circular path, the net force is a special force called the �86�centripetal force�116� (not centrifugal!). Centripetal is Latin for "//center seeking//". So a centripetal force is a center seeking force which means that the force is always directed toward the center of the circle. Without this force, an object will simply continue moving in straight line motion. Imagine swinging a rope with a mass attached to the end, around in a circle above your head: Compare each of the following animations to the original one in the top left. Look carefully for what has changed in each one. > **centripetal acceleration** ac = v2 / rThe units are as follows: ac - centripetal acceleration, v2 - velocity squared of an object, r - radius of a circle around which an object is moving. What this means is that the weight is being pulled toward the center of its revolution by the forceapplied to it. It never gets to the center however. It has two motions. One is an acceleration toward the center and the other is a constant velocity perpendicular to that acceleration. At each instant in time it is moving toward the center and at the same time it moves away from it. ||
 * [[image:http://www.regentsprep.org/Regents/physics/phys06/bcentrif/lrlmlv.gif width="259" height="284" align="center" caption="lrlmlv.gif (16274 bytes)"]] || [[image:http://www.regentsprep.org/Regents/physics/phys06/bcentrif/lrsmlv.gif width="259" height="284" align="center" caption="lrsmlv.gif (13932 bytes)"]] ||
 * * The smaller the mass, the smaller the centripetal force //(shown by the red vector labeled as the force of tension in the rope, FT )// you will have to apply to the rope. ||
 * [[image:http://www.regentsprep.org/Regents/physics/phys06/bcentrif/lrlmsv.gif width="259" height="284" align="center" caption="lrlmsv.gif (23137 bytes)"]] || [[image:http://www.regentsprep.org/Regents/physics/phys06/bcentrif/srlmlv.gif width="259" height="285" align="center" caption="srlmlv.gif (14927 bytes)"]] ||
 * * The smaller the velocity of the object, the less centripetal force you will have to apply.
 * The smaller the length of rope (radius), the more centripetal force you will have to apply to the rope.
 * Notice that the centripetal force and the centripetal acceleration are always pointing in the same direction.


 * Citations** [|www.regentsprep.org/Regents/physics/phys06/bcentrif/default.htm]


 * Additional Resource**