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Jim agrees --- its difficult to preserve kinetic energy when
velocities get large.
Having recently seen a little rocket plant itself neatly on a
dime --- Jim has decided to propose yet another
improvement upon dissipating kinetic energy into the
atmosphere.
Jim takes two PVC tubes, plugs
one end of each and
connects them via a sturdy rubber pipe. He buries the two
PVC tubes vertically in the backward with the open end of
each slightly above ground. Now Jim places a PVC plug in
both open ends so that a tight seal is made between the
plug and the tube.
Jim labels the pocket landers A and B.
Having previously purchase two little rockets Jim places
one rocket on A and lands the other rocket on B.
Jim has conserved kinetic energy.
autohorn-blowing
Orbital_20Hovercraft
tangential landing proposed in massive footnote [FlyingToaster, Feb 14 2018]
teeter-totter with a moveable fulcrum
https://a.1stdibscd...67_1312250361_5.jpg
[FlyingToaster, Feb 14 2018]
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Sturton wonders if Jim is trying to rake together the ingredients for a fish stock. |
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Jim has yet to make the acquaintance of the well-documented physical phenomena known as the "Coefficient of Friction" and "Coefficient of Restitution" |
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In the situation described, neither energy nor momentum will be conserved. Frictionless pistons are not widely known to exist. Perfectly incompressible fluids with zero viscosity do exist, but working at temperatures below 20 K is challenging due to material embrittlement; PVC is unsuitable. |
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[8th] in your comment there you sound almost as if
you're criticising this idea from a standpoint of
understanding it! |
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Jim might be better off with a teeter-totter
apparatus. Not as a replacement for his rocket pipe
thingy, but simply as something to entertain himself
with. |
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Better, a climbing frame, and a length of rope tied into a noose. |
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We would certainly find Jim's antics entertaining in such circumstances. Does anyone else want to take a turn pulling on Jim's legs ? |
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8th, Seeing as how the active population of the
bakery is down
to about 10 people or so, I’d like to keep from driving
more
out the door. |
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Jim disregards this input as the enfeebled mumbling
nonsense of the no longer potentates... |
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Given the evident intellectual stature --- the backyard is
large. Not large enough to accommodate intergalactic
rocket ships as suggested --- but large. In any case, there
are no super conductors or absolute zeros (and no
infinities either). PVC and sturdy rubber are
quite suitable for all the input loads. |
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It is likely that a different and liberal application of PVC
and sturdy rubber is required to improve the tenure of
the commentary?! |
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Perhaps a different language would suit. My Klingon
is rusty. T'Poyr Keh'plekh-nghaahr? |
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// Jim disregards this input as the enfeebled mumbling nonsense of the no longer potentates.. // |
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// I’d like to keep from driving more out the door. // |
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But we do not seek to drive him out of the door; we want him to stay, twisting in the breeze on the end of a rope, while the crows peck out the last shreds of his eyeballs, and his bones bleach in the sun (if any). |
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Ignoring the balls and the landers, I *think* this is an idea for
having two rockets push against each other. I suppose you would
build up pressure in the tube between the rockets in somewhat
the same way as you build up pressure in the breech of a cannon,
but slowly and leakily, and then you have to share the resulting
pressure between two projectiles. |
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Am I doing it an injustice? |
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I don't think Jim is talking about the theoretical limit of recovering *all* of the energy of the landing rocket; merely that some portion would be re-used. (The enviro-politician's "conservation of energy", not the physicist's.) |
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When the landing rocket is crushed on impact with B, a fully conserved energy transfer with a zero viscosity incompressible fluid would probably crush the ready rocket at A against its own inertia (assuming it's loaded with a fair mass of propellant, as rockets often are - unlike the "little rocket" types which don't do precision landings) |
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// merely that some portion would be re-used... |
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All energy is conserved of course --- but yes having
rockets land back where they started does not conserve
energy in any any useful way. |
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// A fully conserved energy transfer with a zero viscosity
in-compressible fluid would probably crush the ready
rocket at A against its own inertia |
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Yes... a difficult problem scaled up to adult /
interplanetary proportions. To be honest there is not
much to add |
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Just have one rocket, but make it out of bounciness. |
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I think they call that a slingshot. |
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Well - since there so much wasted effort in this... |
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- Salt the landing pad A with 2-centimeter-wide
piezoelectric generators “stacked like quarters,” |
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- Better yet ionize the atmosphere within each PVC tube
and
wrap the apparatus in coils of conductive wire. |
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- Hmm ionize the rocket exhaust and stick it though coils
of conductive wire. |
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- Land each rocket on a bouncy castle and have a small
child double jump it when required |
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Perhaps Jim might develop a way of intermingling the rocket exhaust with, just as a suggestion, cats ? |
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It's a cheap and simple way of converting fishbones into buns ... |
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The optimal solution is to have a constant, equal jerk on both rockets. |
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So - ignoring stuff like friction, media momentum, etc - |
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This could be accomplished by launch/land on top free-floating pistons which magically change diameter to accomodate the slope of the funnel-shaped (downwards opening) "cylinders" in which they ride.
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Of course, the solution which doesn't require magic is tangential landing/launch to/from an equator-based linear accelerator <link>. |
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Too simple, too practical. |
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// equal jerk on both rockets // |
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[madness] on one, Jim on the other ? |
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//teeter-totter// with a non-stationary fulcrum. |
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For simplicity, just put the pivot at one end. |
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//pivot at one end// Like an atlatl? |
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//Like an atlatl?// No thanks, but a G&T wouldn't go amiss. |
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