simple physics ball roller

RollABallTiny

// uncomment this line if using new input system:
// #define USE_NEW_INPUT_SYSTEM

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

// @kurtdekker
//
// - put this on a sphere
// - use arrow keys to move it
//

public class RollABallTiny : MonoBehaviour
{
	[Header("Adjust to suit:")]
	public float MoveForce;
	public float JumpForce;

	private void Reset()
	{
		MoveForce = 25;
		JumpForce = 250;
	}

	Rigidbody rb;
	private void Start()
	{
		rb = GetComponent<Rigidbody>();
		if (!rb) rb = gameObject.AddComponent<Rigidbody>();
	}

	Vector3 commandForce;
	bool jumpRequested;

	void Update()
	{
		commandForce = Vector3.zero;

#if USE_NEW_INPUT_SYSTEM
		// new system: InputAction, Keyboard.current, etc.
		if (Keyboard.current.leftArrowKey.isPressed) commandForce.x = -1;
		if (Keyboard.current.rightArrowKey.isPressed) commandForce.x = +1;
		if (Keyboard.current.upArrowKey.isPressed) commandForce.z = +1;
		if (Keyboard.current.downArrowKey.isPressed) commandForce.z = -1;
		if (Keyboard.current.spaceKey.wasPressedThisFrame) jumpRequested = true;
#else
		// old system: Input.GetKey, Input.GetAxis, etc.
		commandForce = new Vector3(
			Input.GetAxisRaw("Horizontal"),
			0,
			Input.GetAxisRaw("Vertical"));
		if (Input.GetKeyDown(KeyCode.Space)) jumpRequested = true;
#endif

		commandForce *= MoveForce;
	}

	private void FixedUpdate()
	{
		rb.AddForce(commandForce);

		if (jumpRequested)
		{
			jumpRequested = false;

			rb.AddForce(Vector3.up * JumpForce);
		}
	}
}