Keep gravity while adding velocity to a Rigidbody?

Questions & Answers
1

Little help for a newbie.
So I have a player “sphere” which moves around on the x using addforce with the a and d keys. I tried to implement a jumping feature, but I have this issue where the ball, if force is added on the x on during the fall, will seem to be unaffected by gravity and move only to the side where velocity is added. Here is the code:

using UnityEngine;
using System.Collections;

public class movementx : MonoBehaviour {

	public int speedleft;
	public int speedright;
	public int jump;
	public int downjump;
 	public Rigidbody ball;

	void Update () {
	


	if (Input.GetKey (KeyCode.D)) {
			ball.velocity = Vector3.zero;
			ball.angularVelocity = Vector3.zero;
			ball.AddForce (speedleft, 0, 0);
		} else if (Input.GetKey (KeyCode.A)) {
			ball.velocity = Vector3.zero;
			ball.angularVelocity = Vector3.zero;
			ball.AddForce (speedright, 0, 0);

		} else if (Input.GetKeyDown (KeyCode.Space)) {
			ball.velocity = Vector3.zero;
			ball.angularVelocity = Vector3.zero;
			ball.AddForce (0, jump, 0);
		}
	}
}

Thanks again for the help!

2

Remove this:

ball.velocity = Vector3.zero;
ball.angularVelocity = Vector3.zero;

Also, you will need to reduce speedleft, speedright, and jump.