an object of mass 0.5 kg is whirled at the end of a string 0.8 m long. if the string makes 3 revolutions in 1.2 sec. find the tension in the string.

Question

anonymous · Answer

T = centripetal force+weight
weight=mg
Centripetal force = m*w^2 rad 
now, after calculating that, you add them.

ujjwal · Answer

@physicsme  I don't think you will need weight here.. If it makes a horizontal circle, tension and weight are perpendicular to each other, and so the component of weight in the direction of tensile force is zero.. and the tension is independent of weight.. 
If its a vertical circle, tension varies at every point.. It is max at bottom of circle and min at top of circle..

anonymous · Answer

@ujjwal  yes, when it makes a horizontal, then weight will be zero.
But as you said, at the top or bottom, the tension is maximum.and  for  this question we will calculate the maximum tension that the string can endure.