What Factors Influence a Boat's Trajectory Under a Bridge?

[Numeriprimi]

When I went today after the bridge over the river, I thought... It's about how I see the situation. I noticed that just below me (under the bridge) was situated bow boat, sailing directly under the bridge. For how long, the boat will be on second side?
How will the solution be different if I go on evenly, from a case if I stood on the spot?How to express numerically? It will be something very complicated geometry, or what will?

Thanks very much... And sorry for my bad English.

 

[tiny-tim]

Hi Numeriprimi!

If you are walking across the bridge, and the boat is sailing along the river,

then i don't see how your speed will make any difference to when any part of the boat crosses under the bridge.

 

[CWatters]

How does the boat know you are there?

 

[pongo38]

I recommend using vector analysis in 3 dimensions.