help!help!why did not it tirgger???

Unity Engine
1 
var otherCollider : Collider;

function OnCollisionEnter(collision : Collision)
{
    var contact : ContactPoint = collision.contacts[0];
    print("This collider collided with: " + contact.otherCollider.name);
}

i am making a game like fruit naja,now i want to the name of the fruit which was cut by knife,fruit and knife all attached Box and Rigidbody,

But when i run the game ,the fruit was cut with nothing happen ,i want the name……

is the code wrong or the ‘OnCollisionEnter’ not working?

2

Are either marked as being kinematic?

3

no ,the fruit did’t,cause i need to give the fruit a muzzle velocity ,if i elected the kinematic,there is a error:

Actor::setLinearVelocity: Actor must be (non-kinematic) dynamic!
UnityEngine.Rigidbody:set_velocity(Vector3)

there is another way to achieve collision judgement?

it is a grateful to show me a case of code

thank you!