Apple Product Design Engineer, interview questions

The interview is very intense. The virtual onsite interview takes a whole day with 7~8 meetings with different engineers. Interviewers are harsh and ask a lot of technical questions, not very nice.

The questions were basic mechanical eng questions, I.e. stress/strain graph, beam bending, etc. I was then given a design challenge and spent two days interviewing back to back. I then presented my challenge. Overall it was good but there was guy on the last day that was a massively rude. He asked me the deflection eqn and then asked me multiple time if I was sure. It had me a bit shaken up and I looked it up later and saw that I was right. If it wasn’t for him I would have liked it more