Rigidbody2D is falling slowly when using velocity

Questions & Answers
1

I am making a super mario style game. I have attached a rigidbody2d to my player and a script to make him run. When you run while falling, the gravity slows down. It works exactly how I want it to until this happens. The scene is at a reasonable scale (1, 1, 1) and the gravity works fine.

Here’s the script-

//MarioMove.cs
using UnityEngine;
using System.Collections;

public class MarioMove : MonoBehaviour {
	public Animator marioAnimator;
	public bool canJump;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void LateUpdate () {
		if(Input.GetKey(KeyCode.RightArrow)) {
			transform.eulerAngles = new Vector3(0, 0, 0);
			GetComponent<Rigidbody2D>().velocity = new Vector2(5, 0);
		}
		if(Input.GetKeyDown(KeyCode.RightArrow)) {
			marioAnimator.SetBool("Run", true);
		}
		if(Input.GetKeyUp(KeyCode.RightArrow)) {
			GetComponent<Rigidbody2D>().velocity = Vector3.zero;
			marioAnimator.SetBool("Run", false);
		}
		if(Input.GetKey(KeyCode.LeftArrow)) {
			GetComponent<Rigidbody2D>().velocity = new Vector2(-5, 0);
			transform.eulerAngles = new Vector3(0, 180, 0);
		}
		if(Input.GetKeyDown(KeyCode.LeftArrow)) {
			marioAnimator.SetBool("Run", true);
		}
		if(Input.GetKeyUp(KeyCode.LeftArrow)) {
			GetComponent<Rigidbody2D>().velocity = Vector3.zero;
			marioAnimator.SetBool("Run", false);
		}
	}
	void Update () {
		if(Input.GetKeyDown(KeyCode.UpArrow)) {
			if (canJump == true) {
				GetComponent<Rigidbody2D>().AddForce (transform.up * 300);
				canJump = false;
			}
		}
	}
	void OnCollisionEnter2D(Collision2D coll) {
        if (coll.gameObject.tag == "Ground") {
            canJump = true;
        }
    } 
}
2

Figured it out myself! Used this code-

//MarioMove.cs
GetComponent<Rigidbody2D> ().velocity = new Vector2 (-5, GetComponent<Rigidbody2D>().velocity.y);

Hope this helps somebody!