How to Stop Continuous Collision with GameObject

Questions & Answers
1

When i hit EnemyObject with Arrow to decrease health by 50, but i happens 50+50 = 100 at one shot, So enemy die at single shot
already i have selected rigidbody collision detection is Discrete, but two or more times collided each other to decrease health, how to solve this problem,
here is the Code…
public void OnCollisionEnter(Collision others) {

    		if (others.gameObject.tag == "Arrow") {
    			EnemyHealth = EnemyHealth - 50;
    			EnemyHurt.Play ("hurt");
    		
    			Debug.Log ("EnemyHealth :" + EnemyHealth);
    		}

I need only decrease 50 only once but EnemyHealth is decreases two or more times…Please solve this problem

2

usually projectile tells object that it was just attacked.

So on HealthAndDamage script attached to attacked object in Update you have this

if (justAttacked == true && hitByArrow)
{
EnemyHealth = EnemyHealth - 50;
EnemyHurt.Play (“hurt”);
Debug.Log (“EnemyHealth :” + EnemyHealth);
justAttacked =false;
}

on arrow you have this code

if (hit.transform.tag == enemyTag )

{

HealthAndDamage HDScript = hit.transform.GetComponent();
HDScript.iWasJustAttacked = true;

}