physics involves a deep understanding of topics rather than repetition, which is the case with maths. It is very interesting but does require a lot of time if you don't quite understand a topic. Maths is probably easier in that if you practice loads you will do well, but with physics no matter how much your practice, if you don't understand the underlying concepts you won't do as well. If you are good at maths you will probably do well in physics as physics involves maths.