add force when something hit in unity code example

Example 1: unity how to add force

public Rigidbody rb;

if(Input.GetKey(KeyCode.W))
{
	rb.AddForce(100, 0, 0);
}

Example 2: how to add a force to an object unity

private Rigidbody2D rb;
public Vector2 direction;
public float force;

void Start()
{
	rb = GetComponent<Rigidbody2D>();
    rb.AddForce(direction * force, ForceMode2D.Impulse);
    //rb.AddForce(--pass in Vector--, --can pass in ForceMode--);
}