[b]1. The problem

Calculate the tension in a 3m string attached to a 3kg bob that is moving in horizontal circles of a 0.6m radius

[b]2. Relevant equations

The only formula i have been able to find is tension = mass1 w2 with w2 being the circumfance but this does not that in to account gravity or the length of the string

[b]3. The attempt at a solution

i know the circumfance is .6 x 2 x pie which is 3.7692 but should this figure be timesed by gravity? ive spent 2 hours looking for other formulas but have had no luck. Excuse the less than great english. Im not so much after an answer but a way of getting there

Thanks