1.Experimental Test of F=Mrω2 by Whirling a Rubber Bung

Physics Practical
TAS Lab Report
Experimental test of Fc=mrω2 by whirling a rubber bung

CHUI, WING LAM CYNTHIA
6B (3)
GROUPMATES: ANDY TAM, TOMMY LO
Date of experiment: 26-01-2011
Date of submission: 21-02-2011
I. Objective For a body moving in a uniform circular motion, measure the centripetal force acting on it and compare it with the theoretical value Fc=mrω2.
II. Theory
|Fc=mrω2 =Mg |where |Fc is the centripetal force |
| | |m is the mass of the rubber bung |
| | |M is the mass of 3 crew nuts |
|Let |T be the tension in the string |
| |L be the length of the string between the bung and the upper opening of the tube|
| |ω be the angular velocity of the rubber bung |
| |r be the radius of the circular path |
| |θ be the vertical angle of the string |

Centripetal force is the centrally directed net force acting on the body. It provides the centripetal acceleration which keeps the body moving in a circle according to Newton’s Second law (Fnet=ma). In this experiment, the tension is provided by the weight of screw nuts and the centripetal force is supplied by the tension. The tension in the string is resolved into two components(Tsinθ and Tcosθ).As there is no vertical motion, the vertical component of tension is balanced by the weight of the rubber bung (i.e. Tcosθ=mg).The horizontal component of the tension provides the net centripetal force (i.e. T=mLω2). By comparing the two values of tension, the expression of centripetal force (Fc=mrω2) can be verified
III. Apparatus
|Rubber Bung x1 |Adhesive Tape x1