Finding an equation for the speed of a ball

[goomstooms]

Homework Statement

A small ball rolls around a horizontal circle at height y inside the cone. Find an expression of the ball's speed in terms of a, h, y and g

Homework Equations

Newton's third law

The Attempt at a Solution

I am not sure how to approach this problem

 

[tiny-tim]

Newton's third law

No, use Newton's second law …

force = mass times acceleration, plugging in the formula for centripetal acceleration