Recent content by softport

Thanks for all your answers. I did not think about rotating frames, only the effects between 2 masses in the same inertial frame. To frame the problem in a more realistic way, I would have to go back and watch this great series of lectures by prof Sarma at MIT. I have watched these at least...

Thanks for all your answers. I did not think about rotating frames, only the effects between 2 masses in the same inertial frame. To frame the problem in a more realistic way, I would have to go back and watch this great series of dynamics lectures by prof Sarma at MIT. I have watched these at...

Hello, where did you read this? I was having a hard time trying to think of the difference, then found this on Wikipedia: "In electrical engineering, two conductors are referred to as mutual-inductively coupled or magnetically coupled when they are configured such that change in current flow...

I tried to answer my question above, and found this paper that mentions a possible graviton mass of 1.3x10-69 kg . Now, how far would a single hydrogen atom have to be, from earth, till it's potential energy due to Earth's gravity is below the energy of one graviton (E = mc2)? What came out...

Thanks phyzguy, my thoughts were that it's not far from Earth that you have things floating around in space (albeit with outward force from orbiting). I guess given that gravity extends to infinity, the surprising thing should be that there is an escape velocity at all. Naive question: if...

Hello, can you can tell me if this is correct? I thought the height would turn out close to where satellites orbit, but it comes out to about 5.5 million miles away! I was very surprised by this, that's about 20 times further than the moon. Here's what I used Escape velocity: Ve = sqrt(2GM/r)...

I found this in Wikipedia: A problem occurs to me though. Even if you determine that there is a hole, but it's not big enough to cause a problem: how can you be sure that it won't get bigger over time?

Thanks huntoon, that does clear thing up a bit. I didn't know about the 12000 btu standard. I did spend some time trying to understand the 'money quote', but I interpreted it to mean that simply converting the Btu rating to watts would underestimate the power consumed. In light of the 12000...

Thanks huntoon, but according to the above you should get the following: 6000btu x 0.293071 = 1758 watts (!) The cooling and efficiency specs get even worse if you include the power used by the fans and electronics: From the specs in the example link: Total power 115v x 5.4A = 621W...

Maybe assumption 2 is incorrect? You could check the pressure drop for longer periods, see if it levels off. I'm basing this on the assumption that while you are pressurizing the vessel, the temperature of the air inside will end up higher than ambient, and the pressure will drop as it...

Hello, I am confused about air conditioner Btu specs. When I try to match the power input in watts, to power out in Btu/hr, the numbers don't come out even close. Example: This 6000 Btu window unit has the following specs: Volts 115 Amps 5.4 So the power input in watts is: 115 x 5.4 = 621w...

Thanks torquil, I didn't find this on my searches. I'll study it and post back. regards

Hello, is it possible to write a Lagrangian (L) for a simple RC (or RL) circuit? Normally L = kinetic - potential energy, but how would you write this for an RC circuit? thanks!