Recent content by awygle

Hey everyone, I'm looking for some references on solenoid design - core materials, geometry, etc etc etc. Can anyone suggest me some canonical references that I should check out? All the books I've found are from the 60s or so. Thanks!

Homework Statement An airplane travels 1250 km/h around the Earth in a circle of radius essentially equal to that of the Earth, returning to the same place. Using special relativity, estimate the difference in time to make the trip as seen by Earth and airplane observers Homework...

This may be hard to explain, but here goes... Say you have one of those little plastic BBs. When there's just one, it behaves like a solid sphere (which it is). But if you have a large number of them, the mass sort of acts like a liquid - it pours and flows and similar things. My questions...

So I've been reading up on optical rectennas, and the sources I read say that the reason such devices are not yet efficient enough to be practical isn't the antenna, it's the rectifier, since solid-state Schottky diodes of the types normally used don't work in the THz range of AC frequencies...

I'm trying to work out the mathematics of this, just for fun/practice. What I thought I'd do was calculate what the accelerations/velocities/jerks would have to be to a) slow the ship down and b) keep it moving in the same orbit. For that to happen it would have to be the case that...

This is something I've wondered for some time. Our spaceships need all this ablative heat shielding because they slam into the atmosphere at ludicrous speeds, thereby generating a ton of friction and heat. Wouldn't it make more sense to slow down first? There is an orbit where the speed of the...

OK, I think I see now. So my problem is that I was interpreting it as an absolute value (kinda), thinking that if |-\frac{\mu}{2a}| was smaller, then it took less energy to reach that orbit. But because it becomes a smaller negative number, it is actually taking more energy, as shown by the...

So what you're saying is that -\frac{\mu}{2a} is the energy with the 0 reference point set at an infinite distance from the Earth, i.e. that it's the energy it would take to reach that orbit from infinity? Or was that just an explanation of the negative sign in the equation?

If specific orbital energy for an elliptical orbit is -\frac{\mu}{2a} , shouldn't that mean that the further from the Earth an orbit is the lower its specific orbital energy? The Wikipedia page on specific orbital energy (admittedly not the best source) indicates the opposite, and if it were...

I'm curious - what would happen if a satellite was in orbit around an object which suddenly lost a large piece of its mass, or gained a large amount of mass? Of course this seems extremely unlikely to occur in nature, but I suppose similar reactions could be produced by using engines to counter...

Homework Statement A spacecraft orbits around the Earth at a tangential speed v and a radius R, in accordance with the equation a_{c} = \frac{v^{2}}{R} . a) If the spaceship's engines exert a force parallel to its instantaneous vector of motion, what is the effect on the quantities...

I'm confused about some results I've been getting. I tried calculating the equatorial velocity of Earth by the equation R\varpi=v, and I got ~465 m/s. According to various resources, this is correct. But then I tried to calculate it again, using g=a_{c}=\frac{v^{2}}{R}, and I got ~8000 m/s...