Setting rigidbody's force to 0

it's either

         rb.AddForce(new Vector2(-rb.velocity.x  , -rb.velocity.y), ForceMode2D.Impulse); //2d
         or
         rb.AddForce(new Vector3(-rb.velocity.x  , -rb.velocity.y , -rb.velocity.z), ForceMode2D.Impulse); //3d

dependent on what your games dimensions are

rb just means rigidBody so if you don't use rb as a var

     gameObject.GetComponent<Rigidbody2D>().AddForce(new Vector2(-gameObject.GetComponent<Rigidbody2D>().velocity.x, -gameObject.GetComponent<Rigidbody2D>().velocity.y), ForceMode2D.Impulse);

this also works