After my friend sent the referral, the recruiter got back to me very fast. Had a 15-mins phone screening with the recruiter. No technical questions just some background, status, timing stuff. Then I had an interview with a technical manager. I was asked about my experience, especially the ones related to design. Then I was asked the classic cantilever beam questions. Make sure you have a good understanding of the definition of stress, stiffness, buckle, etc. Do review your "Strength of Materials" and "Mechanical Design" courses! Thanks to everyone who contributed here. I passed the first round and went to the second. I got the design challenge named "push-button design for the iPod battery cover". Spent 5 days to make the 3D model and slides. Did some FEA. Was then told they didn't see it as a good match. If they like your design, they will bring to Cupertino.

i had my interview today and was asked the same question. also similarly, the interviewer had no sense of humor. it was not a enjoyable experience because i think i gave like 3-4 different ways of making a cantilever, but i was asked "what else?" like 10 times for the cantilever problem alone. i also have 7 years of work experience, but there was 0 question asked about it.