OnCollisionEnter not called on Unity4.3 for 2D.

I have two 2D object, one is use to throw by catapult and then it hit other 2D object. Both have collider and Rigidbody both have unchecked isKinetic and isTrigger. When they collide with each other then OnCollisionEnter method doesn’t call and script is attached to that object which is thrown by catapult. Kindly if any one face this problem help me on this. Thanks in advance.

2D physics require 2D colliders. Replace Rigidbody components with Rigidbody2D, Colliders with 2D colliders. Replace OnCollisionEnter(Collider col) with OnCollisionEnter2D(Collider2D col).

Have a look HERE for further help.