Recent content by Adrian B

On Wolfram Alpha, I get the following values for gravitational acceleration on Earth due to the sun and moon, respectively: gravitational constant * mass of sun / (distance to sun)^2 → 0.005991 m/s2 gravitational constant * mass of moon / (distance to moon)^2 → 3.68×10-5 m/s2 If the...

Thanks folks!

I've read that tides deform the Earth's crust by about 40cm. When I try to visualize the tidal bulge approaching me and then receding away from me, it seems like the local surface under my feet would tilt slightly one way as the bulge approaches, then level out, and then tilt slightly the other...

Had a power failure about an hour ago and I can verify that the cable system (internet, at least) continued to work.

The OP might be interested to note that the energy received from the decay of Earth's radioactive content ultimately comes from other earlier stars that created those radioactive elements.

I once worked with somebody who had anxiety attacks related to flying but the job required occasional air travel. His doctor gave him an anti-anxiety medication to take before flying and that was enough to get him past that problem. It wouldn't hurt to talk to your doctor about your panic...

Entropy: Have a look at Leonard Susskind's quantum mechanics lectures at http://theoreticalminimum.com/courses/quantum-mechanics/2012/winter. He doesn't assume much prior mathematical knowledge and spends a lot of time in the first few lectures explaining the linear algebra and interpretation of...

I'll second that. Note that the corresponding video lectures are at http://theoreticalminimum.com/courses.

Hi Kostas. You might want to try Leonard Susskind's "Theoretical Minimum" lecture series: http://theoreticalminimum.com/courses

Thanks for the feedback, everybody. I posted this same question on electronics.stackexchange.com and received no comments or answers, so +1 for Physics Forums! Since I'm the only user of this equipment and I wouldn't want charge wasted if the power should happen to fail while I'm not present...

Let me start by saying that the point of this question is to figure out if I can do this with items on hand instead of buying a UPS. I have a cable modem and wireless router which require 12V 750mA and 12V 1000mA respectively. In the event of a power outage, I'd like to be able to manually...

Or, "Same reason we have subtraction and division when we already have addition and multiplication."?

Doesn't the "Big Rip" hypothesis depend on space expanding within bound objects?

Glad you figured it out. I noticed that when you listed the values you didn't specify the units for G. In the future, you can almost certainly avoid the problem you ran into by including units in your calculations. In this case, you would have run into different "km" and "m" units and you...

What values are you plugging into that equation and what are their units?