I'm following a tut - converting to 3d - and confuzzled by RigidBody2d - vector 3

So I'm following a tutorial by Quill18 - attempting to make a 3d arcadey racer - his tutorial is originally for 2d - I've converted most of it - but I've hit a snag.

The following code flags an error "Missing Component RigidBody2d"--- What am I missing?

     rgBody = carModel.GetComponent<Rigidbody>();

     Vector3 ForwardVelocity()
         {
             return Vector3.forward * Vector3.Dot(rgBody.velocity, Vector3.forward);
         }
     Vector3 RightVelocity()
         {
             return Vector3.right * Vector3.Dot(rgBody.velocity, Vector3.right);
         }