Question

An object of mass 0.5 kg is whirled at the end of a string 0.8 m long.If the string makes three revolution in 1.2 s,find the tension in the string.

Answer 1

The tension in the string provides the centripetal force for objects tied to a string & movin in a circular path.

Ft = mv^2/r
where m=mass of d object, v=uniform velocity of d movin body & r=radius of d circle formed by d moving string
1 revolution = 360¡ã or 2pie radians
so 3rev = 2pie * 3radians = 6pie radians
time for 3rev = 1.2secs
angular vel. = ¦È/t
6pie / 1.2 = 5pie radians per sec
since pie = 3.142, so
5 * 3.14 = 15.7radians.sec
Tension = Mv^2/r
=0.5 * 15.7 / 0.8
= 9.81newtons
am not so sure bout d answer but try dis link to understand more wikihow-com/Calculate-Tension-in-Physics