A 500 g ball is whirled around in a (vertical) circle at the end of a 60 cm string so that the velocity at the bottom is 4.0 cm/s. What is the

A 500 g ball is whirled around in a (vertical) circle at the end of a 60 cm string so that the velocity at the bottom is 4.0 cm/s. What is the tension in the string?