How would I solve these two?

A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 60.0 cm, as shown in Fig. 5-33. Its speed is 4.10 m/s and its mass is 0.300 kg.

And

A ball on the end of a string is cleverly revolved at a uniform rate in a vertical circle of radius 60.0 cm, as shown in Fig. 5-33. Its speed is 4.10 m/s and its mass is 0.300 kg.
Find:
a) Calculate the tension in the string when the ball is at the top of its path.

b) Calculate the tension in the string when the ball is at the bottom of its path.

Centrepetal force = mv^2/r

This is the force required to keep the circular path. This is the force that must act on the particle towards the centre at all times for the particle to keep a circular path.

Here m = mass = .3, r = .6 m, v = 4.10

At the top of the path, forces acting on the particle towards centre are (T = tension) and weight mg

mg + T = mv^2/r

At the bottom, forces acting on the particle towards centre are T and -mg :

T - mg = mv^2/r

From the above 2 equations, calculate T in each case by substituting values of m, v, r and g