physics
posted by rohan .
an object of mass 0.5 kg is whirled at the end of string 0.8 m long if the string make three revolution in 1.2 sec find the tension of the string

tension = sum of centrietal force+gravity
notice these are vectors.
tensionvertical= mg down
tensionhorizonal= m w^2 * rad
= .5*(2PI/.4)^2 * .8
now, after calculating that, you add them as vectors
tension= sqrt ( (mg)^2+(horizonalabove)^2 ) 
35.6N