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

public class PlatformMoving : MonoBehaviour {
public float speed = 0.035f;

void Update () {
transform.Translate(speed, 0f, 0f * Time.deltaTime);
}
}

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

public class CollisionPlatform : MonoBehaviour {

void OnCollisionEnter2D (Collision2D moving) {

GameObject platform1 = GameObject.Find("Platform");
PlatformMoving change = platform1.GetComponent<PlatformMoving>().speed = -0.035f;

}

}