JoeWright wrote:I remember seeing a reconstruction programme on BBC about Trebuchets. In it they found that letting the trebuchet move (i.e. wheels, no block) made the projectile go further than a model with no wheels.
Any thoughts on the discrepancy?
Joe
Nice demo btw
Well it seems I have to retract from my interpretation of the trebuchet simulation and my intuition, yes I am wrong from time to time, I am not afraid to admit it,
After seen the later previews of the trebuchet, I have to say the that BBC documentary, JoeRight, this
http://www.pbs.org/wgbh/nova/lostempire ... heels.html The Newton engine, and many other observation of trebuchet, were all right and I was wrong.
I based my assessment on my intuition of conservation of momentum and energy, I assumed that not energy is lost during the firing and therefore a trebuchets that is not allow to move will transfer more kinetic energy to the bullet.
However this is not correct, there is lot of energy lost in the process and it appears the wheels allowed for a more effective transfer of kinetic energy to the ball.
Here is a video showing this in Newton where it clearly shows the counterintuitive result.
http://newtondynamics.com/downloads/Catapult.mpg
Had I not read Joe Wright Observation and base on my intuition I would had spend lots of time trying to find if there was a bug on the formulation of the equations in Newton.
I guest that if the BBC people had Newton and Sascha's Playground they would not had to build the real model to confirm the fact.
These subtle things are important to me, because I do not like inconsistencies.