As long as you can answer their questions adequately, you'll be fine. I answered the sewer cap question with "the caps are heavy and any other shape would be hard to roll away when access is needed to the sewer. Also, a shape with corners could warp and potentially damage tires", etc.
A sewer cap is round because it is the only shape that, when removing the cap, cannot fall into the hole.
This is not always the case.In China the sewer cap could be either round and square.But square one comes in small size.
Mostly questions about my previous experience and the sort of work I would be comfortable with. They asked if I had experience with writing scripts for FPGA (in addition to the responsibilities of the position I was interviewing for).
It was a trick question...critical path should not have any slack
^^That's not exactly true. Tasks on the critical path refer to the tasks with the least amount of slack, or better put, tasks that if not completed first will adversely affect the end date of the project. I've seen some PM's consider tasks with <5 days of slack as their determining factor, others go as high as 10 days. Either way, it wasn't a trick question, the interviewer just wanted to see if you understood what the Critical Path was.
I told them, without thinking, of a time when a group I was working with on a school project came up with a method to cheat on an accounting project (by getting last year's Excel template and simply changing the numbers). I told them I was against the group taking that route, but I didn't want to be the only one that spoke up so I went along with it. Perhaps that wasn't too smart of me.