Recent content by robhlee

Hi, i need help figuring out what to look for in a motor given certain specifications. If I am browsing for a motor that is able to spin at 3500+ rpm while holding 200 lbs. of weight, what attributes/values do i need to pay attention to?

well, as for the advantage over air, i am not quite sure but wouldn't a lot of energy be wasted in compression (heat involved, etc.)? And for the spring, (equation being f=-kx) the distance compressed is the problem when trying to attain high force. that's why pogo sticks are the way they are...

please someone give input and arguments...

Hello I am quite a physics noob and the following is something I wouldn't bet on but is more of physics concept practice. But if it works, great! Specific questions/problems that I would like an answer to will be denoted by a number and the blue twirling smiley(:smile:), for your convenience...

how can i show a picture on this forum (w/o creating a new topic) ?

How fast does a hydraulic machine work? The model i am thinking of is a simple two-sided setup, where the surface areas of the two platforms are different and a tube connects them. In terms of movement of the two platforms, how fast can the machine work. I am just looking for an approximation...

I think the focus of the issue is the hydraulic fluid; I just want to know an approximation of how the fluid would move (i'm just talking about some noncompressible oil; would it differ a lot between types of oils?). Would a hydraulic system be able to work instantaneously/ rapidly in response...

About those hydraulic devices that are used for lifting cars and such; how can you calculate the maximum speed at which those will operate?

If I have one device that uses the eddy current impulse "transformer" stated earlier (w/ explosions of hydrogen), and compare it to a rocket engine with thrust to equal the amount of hydrogen used by the explosion during any given amount of time, the force and change in momentum provided by the...

Hey russ_waters, I knew the heat efficiency of nozzles were much higher than the combustion engine cars, but can you compare them in terms of change in momentum per a given amount of hydrogen?

Oh sorry about the use of "net" early in the post. I meant change. I ll change it. Yes I mean h2 car.

Hey russ_waters, sorry for being thick-headed, but could you give me an example of a pusher-plate? Well what I was getting at, or what I am trying to do, is to use eddy currents (magnet and copper pipe) to "transform", if you will, the impulse of an explosion. That is why I was wondering if...

pusher-plate? do you mean like in a piston?

Hey what if you had a certain volume of hydrogen gas in two different scenarios. They are of equal amounts. In one scenario, the hydrogen is ignited so that it explodes instantaneously. In the other scenario, the (equal amount of) hydrogen is used in a thrust engine for an extended period of...

i am not sure if you got this, but what i meant was ring magnets vs. disk magnets. (dropped through pipe)