Player Movement with Physics Engine

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


//player movement using the physics engine from Ferrone Learning Unity book
public class PlayerBehaviour : MonoBehaviour
{

    public float moveSpeed = 10;
    public float rotateSpeed = 75;
    private float horizontalInput;
    private float verticalInput;

    private Rigidbody playerRB;
    void Start()
    {
        playerRB = GetComponent<Rigidbody>();
    }

    void Update() {

        PlayerMovement();
    }

    private void PlayerMovement() {

        verticalInput = Input.GetAxis("Vertical") * moveSpeed;
        horizontalInput = Input.GetAxis("Horizontal") * rotateSpeed;
       /* transform.Translate(Vector3.forward * verticalInput * Time.deltaTime);
        transform.Rotate(Vector3.up * horizontalInput * Time.deltaTime);*/
    }

    private void FixedUpdate() {

        Vector3 rotation = Vector3.up * horizontalInput;
        Quaternion angleRot = Quaternion.Euler(rotation * Time.fixedDeltaTime);
        playerRB.MovePosition(transform.position + transform.forward * verticalInput * Time.fixedDeltaTime);
        playerRB.MoveRotation(playerRB.rotation * angleRot);
    }
}