player trigger ball falls

I was trying to place a trigger under the sphere so that when my player walks into the trigger, the ball will fall off. How do I write a script to achieve it assuming that we add a Box Collider to the trigger and the trigger is place under the sphere?

Thanks!

//add RigidBody to ball and set isKinematic,Use Gravity to true;
//add this script to Trigger GameObject

public RigidBody ball;

void OnTriggerEnter(Collider other)

{

ball.isKinematic=false;

}