keyboard input not moving object

So here is my code and a view of my inspector for my sphere that I am trying to get rolling around with the roll a ball tutorial. Also an image of my input settings. When I press the W button I get the message "W is pressed" and when I release the button I get the message "W is released"; however, the sphere does not move around. I can get similar messages with other buttons but still no movement. I have adjusted the speed to various values and I have seen similar posts and tried many of the solutions offered but with no success. I am using Windows 10 and Unity 5.3.5f1. Any assistance would be greatly appreciated. Thank you.

Code:

using UnityEngine;

using System.Collections;

public class PlayerController : MonoBehaviour {

 public float speed;
 private Rigidbody rb;

 void start()
 {
     rb = GetComponent<Rigidbody>();
 }

 void Update()
 {
     if (Input.GetKeyDown(KeyCode.W))
         Debug.Log("W is Pressed");
     if (Input.GetKeyUp(KeyCode.W))
         Debug.Log("W is released");
 }

 void fixedUpdate()
 {

     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");

     Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);

     rb.AddForce(movement * speed);
 }

}

!