PROOF - at last!
Moderator: scott
re: PROOF - at last!
Grimer .. I have my thoughts but I already hog too much bandwidth here so thought I'd see if anybody else volunteered to do a sim for you.
Let's see if we can establish the variables & inputs & I'll have a go - you might not like what mr. wm2d has to say though.
I realize the dimensions etc aren't critical but let's agree on some of those.
Intended Action:
The Red bob falls under gravity & strikes the Blue bob arrangement that rotates having gained momentum - at the same time as the Red bob strikes [like a Newton's Cradle] the Green bob is bounced upwards - the whole system gains momentum & rotates.
Inputs:
Blue bobs - 1 kg
Red & Green bobs - 1 kg
Radius - 1 meter
Rods have no mass [to minimize inertia] - the Blue bob system is pivoted but rigid - the Green & Red bob pendulums are also pivoted & independent.
Elasticity of materials steel [0.95] - otherwise standard setting is custom at 0.5 - that means a lot of impact energy & momentum is lost from the system.
Do you want springs before impact ?
While you decide what you want I'll start to throw it together & it can be changed as you like.
If I have misunderstood what you are trying to achieve here correct me & I'll redo it.
As the Red bob falls it's torque contribution to the wheel is lost - therefore the Green bob's remaining torque [previously equalized by the Red] causes the wheel to accelerate CCW.
No springs as yet.
EDIT:
Sim Result:
The Red bob falls CW - as it falls the Green bob has torque & the wheel rotates CCW - the Red bob strikes & bounces upwards - the CCW rotation of the wheel is reversed & the Green bob moves upwards CW still resting on its Blue counterpart - the CoG of the system falls rapidly below the axle & bounces up & down loosing height each oscillation until it comes to rest vertically beneath the CoR at its position of lowest Pe.
Let's see if we can establish the variables & inputs & I'll have a go - you might not like what mr. wm2d has to say though.
I realize the dimensions etc aren't critical but let's agree on some of those.
Intended Action:
The Red bob falls under gravity & strikes the Blue bob arrangement that rotates having gained momentum - at the same time as the Red bob strikes [like a Newton's Cradle] the Green bob is bounced upwards - the whole system gains momentum & rotates.
Inputs:
Blue bobs - 1 kg
Red & Green bobs - 1 kg
Radius - 1 meter
Rods have no mass [to minimize inertia] - the Blue bob system is pivoted but rigid - the Green & Red bob pendulums are also pivoted & independent.
Elasticity of materials steel [0.95] - otherwise standard setting is custom at 0.5 - that means a lot of impact energy & momentum is lost from the system.
Do you want springs before impact ?
While you decide what you want I'll start to throw it together & it can be changed as you like.
If I have misunderstood what you are trying to achieve here correct me & I'll redo it.
As the Red bob falls it's torque contribution to the wheel is lost - therefore the Green bob's remaining torque [previously equalized by the Red] causes the wheel to accelerate CCW.
No springs as yet.
EDIT:
Sim Result:
The Red bob falls CW - as it falls the Green bob has torque & the wheel rotates CCW - the Red bob strikes & bounces upwards - the CCW rotation of the wheel is reversed & the Green bob moves upwards CW still resting on its Blue counterpart - the CoG of the system falls rapidly below the axle & bounces up & down loosing height each oscillation until it comes to rest vertically beneath the CoR at its position of lowest Pe.
- Attachments
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- Grimer1.wm2d
- (13.67 KiB) Downloaded 175 times
re: PROOF - at last!
Nope. It isn't allowed to rotate counter clockwise. There is a stop, obviously.Fletcher wrote:The Red bob falls CW - as it falls the Green bob has torque & the wheel rotates CCW.
Thus the 5 bobs don't start moving clockwise until the falling arm has struck.
Also, the variables have to be massaged until one has a situation where the bounce exhausts itself at the instant the red bob catches the bob above and is held. At this point the system is in perfect equilibrium and any rotation left in the whole system will carry it round to the next release point.
The trouble with sims is unless you know exactly what assumptions are being made you don't know what's going on. And it's probably easier to code the situation oneself than to understand someone else's program.
But thanks very much for your input, Fletch. The path to Rome begins with a single step.
I believe you are a pilot - so you know all about complicated interactions of multiple variables.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
re: PROOF - at last!
Was a pilot at one time - yes, managing multiple variables.
It looks like WM won't be any good to you - someone else might like to try.
I had anticipated your answer & already built a sim like you suggested.
There is a one-way clutch bearing in the center which only allows CW rotation - the bobs are changed to 100% elasticity to act like perfect springs.
Result:
The red bob bounces but doesn't quite meet the blue bob - that's because the red bob gives some of its momentum to the system starting a CW rotation - the whole assembly rotates CW & eventually the red bob does meet its blue bob above it - but by that time there is no residual rotation of the wheel, it has stopped.
That's not surprising for a sim program to be energy conscious.
Sorry & good luck.
It looks like WM won't be any good to you - someone else might like to try.
I had anticipated your answer & already built a sim like you suggested.
There is a one-way clutch bearing in the center which only allows CW rotation - the bobs are changed to 100% elasticity to act like perfect springs.
Result:
The red bob bounces but doesn't quite meet the blue bob - that's because the red bob gives some of its momentum to the system starting a CW rotation - the whole assembly rotates CW & eventually the red bob does meet its blue bob above it - but by that time there is no residual rotation of the wheel, it has stopped.
That's not surprising for a sim program to be energy conscious.
Sorry & good luck.
- Attachments
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- Grimer2.wm2d
- (14.84 KiB) Downloaded 179 times
You anticipated my answer very well as you can see from the following. That's what I was afraid of. I see no reason to imagine that altering the weight ratios would change things either.
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Look at the situation logically. The five bobs are stationary until the red bob impacts. At that instant the red bob starts moving back up CCW and the blue bob starts moving downwards CW towards the red bob. If one can find a set of variables so they they manage to contact each other and the system as a whole still has some CW momentum then one is home and dry. The rotation carries on until the green bob is released at 2 o'clock.
Otherwise - back to the drawing board. It won't be the first time.
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Look at the situation logically. The five bobs are stationary until the red bob impacts. At that instant the red bob starts moving back up CCW and the blue bob starts moving downwards CW towards the red bob. If one can find a set of variables so they they manage to contact each other and the system as a whole still has some CW momentum then one is home and dry. The rotation carries on until the green bob is released at 2 o'clock.
Otherwise - back to the drawing board. It won't be the first time.
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Re: re: PROOF - at last!
I've been thinking again about that question and trying to find an argument why springs might be relevant. I don't want to waste your effort without good reason.Fletcher wrote:
Do you want springs before impact ?
If we regard the impact as the Carnot adiabatic leg then it could be argued that having an impact zone of negligible length is equivalent to a Carnot adiabatic leg of negligible length - in which case of course no energy would be generated.
So it does seem worth while to examine the spring case. One wouldn't want to leave that tern unstoned just in case it later bit us on the bum.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
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re: PROOF - at last!
Grimmer,
At 6 as the wheel turn you will have 2 unwanted bumps that you did not take note of witch will undo all your impetus.
At 6 as the wheel turn you will have 2 unwanted bumps that you did not take note of witch will undo all your impetus.
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re: PROOF - at last!
Grimmer,
If the green bob is lying on the blue bob the instant the red bob drops the wheel will turn ccw as it has lost the red bob on rh side, if the red bob bounces back to the top blue bob is it going to be constraint or will it come falling down, witch it will dangle at 6 till the next blue bob comes around and wack into it. Also , the moment the red bob falls onto the bottom blue bob the green bob will will shoot up (impacted with blue bob)with the same force but counter , as the impetus from the red bob falling , for it is constraint to the wheel.
If the green bob is lying on the blue bob the instant the red bob drops the wheel will turn ccw as it has lost the red bob on rh side, if the red bob bounces back to the top blue bob is it going to be constraint or will it come falling down, witch it will dangle at 6 till the next blue bob comes around and wack into it. Also , the moment the red bob falls onto the bottom blue bob the green bob will will shoot up (impacted with blue bob)with the same force but counter , as the impetus from the red bob falling , for it is constraint to the wheel.
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re: PROOF - at last!
Grimmer,
In fact . the wheel would not even move,
so j.m. may change his smiling face.
In fact . the wheel would not even move,
so j.m. may change his smiling face.
Re: re: PROOF - at last!
You haven't been following - and the name is Grimer, not Grimmer.daanopperman wrote:Grimmer,
If the green bob is lying on the blue bob the instant the red bob drops the wheel will turn ccw as it has lost the red bob on rh side, if the red bob bounces back to the top blue bob is it going to be constraint or will it come falling down, witch it will dangle at 6 till the next blue bob comes around and wack into it. Also , the moment the red bob falls onto the bottom blue bob the green bob will will shoot up (impacted with blue bob)with the same force but counter , as the impetus from the red bob falling , for it is constraint to the wheel.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
re: PROOF - at last!
Grimer wrote:
The one who finishes second remembers........and remembers........and remembers.........
"If you cannot win, make the one ahead of you break the record."
.No one remembers who comes second
The one who finishes second remembers........and remembers........and remembers.........
"If you cannot win, make the one ahead of you break the record."
Love it quick. You ain't gonna have it long.
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re: PROOF - at last!
Grimer,
it won't happen again, still even if you have a stop in the axel the system is unbalanced not in your favour , and you have to overcome this imbalance before you can have access to impetus.If you could release both red and green same time with green falling not on the wheel but on the axel it would have been different. It comes back to every action.
it won't happen again, still even if you have a stop in the axel the system is unbalanced not in your favour , and you have to overcome this imbalance before you can have access to impetus.If you could release both red and green same time with green falling not on the wheel but on the axel it would have been different. It comes back to every action.
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You guys don't have to believe me, but 1 hour ago there was a what seemed like low and very bright object (way too low for a satelite, plus I know what a satelite looks like) crossed the sky. Intensley bright with spikes of light (like a star). Noiseless. Appeared to occasionally jump back then accelerate very fast (that could be eye accomodation problems). Thought 1: it's a sattelite. Thought 2 it's a UFO alien spacecraft but there is no such thing. 3 it's a helico, but no noise. Thought 4, Could be some stealth device. Thought 5, better check out what's up on the forum. Visual before surounding property (got a big yard) hid it : 1 minute. Tommorow I'm keeping a camera handy. And the bow and arrows. "Man shoots down alien spacecraft with bow and arrow, captures crew".
BTW, what happens when a OB wheel is released from "12" , eg where does the strain go ? lemme tell ya, it goes into whatever is holding the wheel. Stop holding what is holding the wheel or you won't get anywhere :)
BTW, what happens when a OB wheel is released from "12" , eg where does the strain go ? lemme tell ya, it goes into whatever is holding the wheel. Stop holding what is holding the wheel or you won't get anywhere :)
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re: PROOF - at last!
one less pull next time brother, they are making it better nowadays
Si mobile in circumferentia circuli feratur ea celeritate, quam acquirit cadendo ex
altitudine, quae sit quartae parti diameter aequalis ; habebit vim centrifugam suae
gravitati aequalem.
altitudine, quae sit quartae parti diameter aequalis ; habebit vim centrifugam suae
gravitati aequalem.