How to identify that moment when two circles are in contact or not

I have two circle. one circle in coming towards second circle from certain height due to gravity. i want to identify that moment when two circle in contact. also if they are in contact which are the contact points on the pheriferi of two circle

Please help me

Answer 1

[Walter Roberson]

Two circles are in contact if the distance between their centers is less than or equal to the sum of the two radii.

[KSSV]

Yes the simple logic.....+1

Answer 2

[KSSV]

You should be having coordinates (x,y) for both the circles. Use this file exchange code to get the intersection of two circles. https://in.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections. If two circles intersect you will get the points, if not no points.