University:
Felician University
Course:
PHYS-355 | Advanced Topics in Physics
Academic year:

2024
Views:

49

Pages:

10
Author:

larbiwxcvbn

Centripetal Force Calculating Centripetal Forces Greater speed and greater mass require greater centripetal force. Traveling in a circular path with a smaller radius of curvature requires a greater centripetal force. Centripetal force, Fc, is measured in newtons when m is expressed in kilograms, v in meters/second, and r in meters. Centripetal Force Adding Force Vectors A conical pendulum is a bob held in a circular path by a string attached above. This arrangement is called a conical pendulum because the string sweeps out a cone. Centripetal Force The string of a conical pendulum sweeps out a cone. Centripetal Force Only two forces act on the bob: mg, the force due to gravity, and T, tension in the string. • Both are vectors. Centripetal Force The vector T can be resolved into two perpendicular components, Tx (horizontal), and Ty (vertical). If vector T were replaced with forces represented by these component vectors, the bob would behave just as it does when it is supported only by T. Centripetal Force The vector T can be resolved into a horizontal (Tx) component and a vertical (Ty) component. Centripetal Force Since the bob doesn’t accelerate vertically, the net force in the vertical direction is zero. Therefore Ty must be equal and opposite to mg. Tx is the net force on the bob–the centripetal force. Its magnitude is mv/r2, where r is the radius of the circular path. Centripetal Force Centripetal force keeps the vehicle in a circular path as it rounds a banked curve. Centripetal Force Suppose the speed of the vehicle is such that the vehicle has no tendency to slide down the curve or up the curve. At that speed, friction plays no role in keeping the vehicle on the track. Only two forces act on the vehicle, one mg, and the other the normal force n (the support force of the surface). Note that n is resolved into nx and ny components. Centripetal Force Again, ny is equal and opposite to mg, and nx is the centripetal force that keeps the vehicle in a circular path. Whenever you want to identify the centripetal force that acts on a circularly moving object, it will be the net force that acts exactly along the radial direction—toward the center of the circular path.