A car is travelling in one direction at 80 km/h and a fly is coming from the opposite direction at 5km/h. (So its velocity is -5 km/h, since it's in the opposite direction.)
The fly hits the windshield of the car and is now travelling at 80km/h. In order for the fly to achieve the speed of 80km/h it's speed must have passed from -5km/h to 80km/h. (Meaning it must pass through the speed of zero) Therefore if the fly passes through a speed of 0km/h and the car is in contact with the fly the car must also pass through that speed of 0km/h.
This seems to mean that everytime a car gets hit by a fly it will completely stop. Why is this not so?
Thinking about this practically, there is no paradox.
When the bee hits the windscreen, it deforms (goes splat -- also the windscreen also deforms ever so slightly, but tends to recover). The first thing to notice is that this is not an instantaneous occurence, but is carried out over a period of time.
As this occurs there is a line that is not moving, and this moves relative to either the bee's bum, or the windscreen at almost 85mph.
[Ignoring these deformations you introduce infinite "hardness" and instanious actions. This is similar to asking what happens when an irresistable force meets an immovable object - no solution as neither of these exist.]
Deformation?
