ArrowController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ArrowController : MonoBehaviour
{

    [SerializeField] float speed;
    public int direction;
    Rigidbody2D rb;

    void Awake()
    {
        rb = GetComponentInChildren<Rigidbody2D>();
    }

    // Update is called once per frame
    void Update()
    {
        rb.velocity = transform.up * -1 * direction * speed;
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        Destroy(gameObject);
    }
}