Quote Originally Posted by Ibrahim View Post
??????

velocity* does actually matter in this situation (the cavalry charge): in fact it's pretty much the only reason there is a force imparted when the lance hits the target (think about it: the horse is pretty much at constant velocity just before impact, as is the the rider). This is because it imparts kinetic energy and momentum to the lance charge**. the kinetic energy is transferred into the target on impact (at least ideally), which is where force comes in (force in this case is kE/s***, where s is displacement--basically the distance the person theoretically recoils back from the blow.

This of course is ideal: we are not accounting for friction here, between the lance and the hand and/or armpit, and between the rider and the horse. nor are we accounting for the person flexing his back, or a host of other factors.


* srsly people: Speed=/= velocity in physics. velocity is a vector quantity.

**kE=0.5mv^2 (v is squared, so matters more than mass). p=mv (p is momentum).

***W=Fscos(theta), where W is work (measured in Joules, as is kinetic energy: they're basically two forms of the same thing), and since the impact is more or less head on, we can ifnore cos(theta), since the cos(0) is 1. so W=Fs, and so F=W/s. substituting W for kE (again, yes, this is fine), we get F=kE/s.
Ah ha. You've proven me right. I don't have a clue what you're on about now... ;p
The way I understand it is that speed=how fast you're moving, acceleration=change in velocity etc. So the force that the cavalry's impact imparts on its target is the effect of the cavalry's mass, multiplied by the difference between the velocities of the cavalry/target. Which I think is what you've written, only in a more accurate (???) way.

As for the cavalry questions.
A cavalry formation is unlikely to be more than a few beasts thick. Going by the number of horse compared to numbers of infantry in classical descriptions of battles, there really isn't that many. Especially when you consider that most of the cavalry (in western-European armies at least) were likely scouts, messengers and skirmishers.
If, and I stress, if, the cavalry have actually charged, and not been driven off, the ranks behind the initial one would be mopping up a broken line, no need for mass or impetus if the infantry are breaking. Wedge formations are more effective for the same reason blades are wedge shaped. It puts a lot of pressure on a small area, making the line easier to break. once among the infantry the sides of the wedge can cause far more damage as there is no longer the surface tension to hold it back. The cavalry in the middle of a wedge are, like the rear ranks of infantry, there to replace the dead, wounded or tired and add greater mass to the unit, not so much in physical terms for cavalry, but psychological.