Sloping off: In the hills south of Rome there is an area which, in the distant past, was volcanic. On the drive from Rocca di Papa to Albano there is a well-known gentle slope in the road which has an extraordinary property.
If you stop your car, put it into neutral and then slowly release the brakes the car will gradually, but perceptibly roll up the hill. I have observed this phenomenon twice, once as a passenger and once as the driver, both in broad daylight. Is there any physical explanation?
Splat: The following paradox has puzzled me since I was a child. A fly is flying in the opposite direction to a moving train. The fly hits the train head-on. As the fly strikes the front of the train, its direction of movement changes through 180掳 because it hits the windscreen and continues as an amorphous blob of fly-goo on the front of the train.
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At the instant it changes direction, the fly must be stationary and since, at that instant, it is also stuck onto the front of the train, the train must also be stationary. Thus a fly can stop a train. Where is the logical inconsistency in this (or does it explain something about British Rail)?