It seemed obvious to me that the deceleration rate would be far less than the normal tyre rubber on road. The answer I got was that this wasn't taken into account. I commented that this would surely make it appear that the motorcycle had been traveling faster than it actually had been. He looked a bit blank but didn't answer.

That's the problem with them, if the situation fits exactly to one of there previous worked problems they can just slot the variables into the various equations and out pops the answers. They have no feel for the engineering of what's going on to spot the none obvious.

Car going up the bum of a stationary object they can manage by just running a 1d solution to and it will work 99% of the time. Things going 2d and they still get it right most of the time. 3d ie things get airborne then they are going for semi educated guesses to try and simplify things down to 2d or 1d which they can work with. The example Shy has of the friction coefficient varying part way through the deceleration process requires calculus to sort out. nae chance comes to mind of plod being able to work it out unless its one of the graduate entry with a clue but they tend to get promoted through the stage of investigating that sort of stuff relatively quickly or don't get near it because its not on the career path to bigger things.