...standing still

The projectile has nothing to do with the system's energy; the energy component is derived from the mass of the counterweight, its falling distance, and the mechanical advantage afforded by the throwing arm. I would say the energy of the system would be potential energy with the counterweight at ground rest and the throwing arm uncocked, and would be stored energy once the counterweight was raised and the throwing arm cocked. Once released from the cocked state, the system would convert the stored energy (the energy used to lift the counterweight and cock the throwing arm) into kinetic energy, which is imparted to the projectile through the rotational force of the accellerating throwing arm. The projectile then would have the kinetic energy of its accelleartion by the action of the throwing arm plus whatever additional kinetic enrgy resulted from the projectile's mass and the force of gravity upon it as measured from the appogee of the projectile's travel path. Take something fairly heavy, put it fairly high into the air, and as it falls, it builds a lotta energy. Generally, a trebuchet is a lofting device, which puts its payload up into the air, causing the projectile to travel over an arc. By the time a trebuchet-launched projectile impacts its target, the major component of its energy comes from gravity.

Timber, forgive me if i am wrong here but isnt potential energy th same as stored energy ie an untensioned spring has no energy a wound up spring has potential energy and a releasing spring has or is imparting kinetic energy.

I think you've sorta got a point there, but the way I look at it, when relaxed, at rest, whatever, its potential energy. If acted upon in such fashion as to rasie or tension or in some other manner store the energy expended to "arm" the device, then I'd say that is "Stored Energy"; its potential has been rendered operable through the application of external energy, and is waiting the condition of being released, at which point the stored energy is expended and the system's energy reconverts to potential energy, waithing to again be readied for release by storing externally applied energy ... did that make sense?

Maybe its a question our young correspondant can take to school on Monday.

Dadpad's right. Here are the first two sentences from wikipedia:

Potential energy is stored energy. The energy is stored by doing work against a force such as gravity or the spring in a clockwork motor.

(bonus homework mark).

If the trebuchet is made mostly of wood, you could burn it to release "stored chemical energy"!

Of course you could - at the cost of no longer having a trebuchet.

(bonus slap across the head from the physics master)

If you had lots and lots of trebuchets then they would start to contract under their own gravity. If you had enough they would collapse and cause an event horizon to form.
Work out the Schwartzchild radius of the resulting black hole's event horizon and how many trebuchets went to make it.
Note : 1 trebuchet weighs about a ton. 1000 kg or 2000 pounds.

:wink:

(bonus Uber-Geek point)

Work out how long it would take for the black hole above to evaporate due to Hawking radiation.
Assume that the average temperature of the universe has dropped below the temperature of the event horizon.

Sure, but that doesn't fit the context of timberlandko's response. His was more of a description of the potential (possibility) for increasing potential (stored) energy.

Burning the trebuchet doesn't project the payload.

Heliotrope.

...and what about the energy released if the trebuchet meets an anti-trebuchet travelling backwards in time !

I've done that fresco.

It's not bad.

Well now there's a conundrum.
Just because it's an anti-trebuchet doesn't mean it's going backwards in time even though that's seemingly one of the solutions to the equations.
But, assuming we have a meeting between a trebuchet and an anti-trebuchet then the energy release would be ...mmmmmmm... ...

About 8.98x10^19 Joules.

That's total conversion though. You'd lose a bit depending because not all of them would come into contact and the other bits would then just be vaporised by the radiation release. Actually then the resulting gasses would be able to interact rather more swiftly and thoroughly so you'd probably end up with a stepped detonation with a large initial energy spike and then a wider peak as the rest of it started to annihilate.
Hmmmm... thinking about shaped antimatter charges now. Wonder what would be the result of a total conversion cone on the continuum structure.
Anyway...
That's a fair bit of energy, in fact it's about the same energy released as a 400 metre asteroid smashing into the Earth at 40 km per second. Roughly.
I reckon that'd would leave an almost 20 km wide crater about 1500 m deep.
So, it's best to be watching this from somewhere out of the way when the anti-trebuchet arrives.
Somewhere like the Moon would do.
Just don't be looking at it when it does though or the gamma radiation might still zap you even there.

Got me thinking now...

A little less Hawkins, and a little more Fermi

How about a trebuchet type fission device. You've got two trebuchets loaded with sub critical quantities of some fissile material (U-235, Th-233 or Pu-239), and you've got them aimed that the projectiles collide in mid air to make a critical mass (with fast not slow neutrons)--could the trebs be placed far enough apart not to burn (additional chemical energy?) in the energy release.

Leading to a practical application for a treb on a nuclear pile--a safety device to throw neutron poisons into a supercritical reactor- providing a trebuchet powered SCRAM.

Rap

Yeah, I reckon that's possible.
It'd be easire to ensure that the launching trebuchets were in the shadow of the resulting energy release from the critical mass.
So arrange for a very deep hole to be dug with a ...
Actually, I'll draw it. It's easier.



You could chuck carbon in there or another neutron moderator using an array of trbuchets around the hole. And also more Pu239 if required.

I hereby request this thread be marked Top secret.

I dont want this information going public as it may be usefull for terrorists.