Horse and Lance Momentum and Energy

  • Context: Undergrad 
  • Thread starter Thread starter Adam
  • Start date Start date
  • Tags Tags
    Charging Force
Click For Summary

Discussion Overview

The discussion revolves around the force delivered by a charging horseman with a lance, exploring concepts of momentum and energy in the context of a potential impact scenario. Participants consider various factors including speed, mass, and the mechanics of the lance's use during a charge.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions the force delivered by a charging horseman and suggests calculating kinetic energy based on the mass of the horse-rider combination and the time to stop after impact.
  • Another participant provides estimates for the mass of the horse, rider, armor, and lance, while expressing uncertainty about how to factor in the elasticity of bodies and the motion of the target upon impact.
  • A different viewpoint emphasizes the importance of "back pressure" from the rider's arm and torso in generating impact force, suggesting that the previously mentioned mass estimates may not be necessary for this calculation.
  • One participant shifts the focus from force to linear momentum and kinetic energy, providing calculations for the momentum and energy of the horse and rider, and discussing the implications of an inelastic collision with a target.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of mass estimates and the mechanics of lance use, indicating that multiple competing perspectives remain without a clear consensus on the best approach to the problem.

Contextual Notes

Participants note the need for assumptions regarding the elasticity of bodies and the dynamics of the impact, which remain unresolved in the discussion.

Adam
Messages
65
Reaction score
1
How much force do you think a charging horseman would deliver with a lance?

Given that a canter speed is approximately 4m/s...
 
Physics news on Phys.org
You would also have to know the mass of the horse-man combination so that you could calculate the kinetic energy. Now you will have to estimate the time that would be required to come to a full stop if they were to charge into a solid wall! Knowing the time required to stop gives you the acceleration and then F= ma.

That gives the maximum possible force. Of course, the force that can be applied is likely to be the smaller of that and the force necessary to shatter the lance!
 
Horse maybe 500 kg.
Man around 90 kg.
Armour example maybe 15 to 25 kg.
Lance 4 or 5 kg.

Target would be a human, say 90kg again, plus armour another 15 to 25 kg.

I'm not sure how to factor in the elasicity of the bodies and the couching arm, nor the fact that the target body will move as it is struck.
 
Actually, I don't think those numbers are really needed. If I understand correctly, the lands was held in one hand and brace against the rider's body. So the real force of impact one could generate with a lance was dependent upon how much "back pressure" one's arm and torso could withstand.
 
Don't ask about force, ask about linear momentum and energy:

the horse and rider has a momentum of
600 kg x 4 ms => 2400 kgm/s
and KE of
1/2 * 600 kg x 4 2=> 4800J

Now we have 100 kg of opponent and we're looking at a totally ineleastic colision, that's going to dissapate about 600 J of energy.

This is comparable to the energy that's in a bullet, but much more momentum.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
7K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 41 ·
2
Replies
41
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 29 ·
Replies
29
Views
3K
  • · Replies 35 ·
2
Replies
35
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K