# losfomot

Senior Members

323

1. ## constant acceleration

Yes, taking relativity into account... how long would it take 'ship time' to get there? I thought there was some (relatively) simple equation that you could use to figure it out.
2. ## constant acceleration

If I were in a ship accelerating toward Vega (26 light years away) at a constant acceleration of 20m/s/s how long would it take for me to get there?
3. ## Speed of Light

Since the boy is HOLDING the mirror there is no relative velocity. The boy and the mirror are stationary relative to one another, no matter how fast the boy might be capable of running.
4. ## Inconsequential gravitational quirk?

You misunderstood me. I never suggested a gravitational field that pulls, although I certainly don't count that possibility out. I'm not trying to 'replace' the effects, I just would like to see a cause as well. We may never be able to say, undeniably, this is how gravity works. But we can certainly discuss possible causes of gravity... can't we? I like it Let's go with that one!
5. ## Inconsequential gravitational quirk?

OK, so far, you're all focusing on the 'radiation pressure' aspect of Drawkcrab's post. Yet even he admits: And so I think that what he (or she) is looking for is a discussion on the idea that something may be pushing everything in the way that he describes. Radiation can be replaced by 'some form of energy' or even simply, 'something'. This idea has intrigued me for a long time, I think I especially like it because it deals (at least partly) with a cause of gravity and not just the effect that Newton and Einstein describe.
6. ## Trig derivatives

Thanks for the help Tom... I got both questions correct now, but I didn't use the chain rule, I used the product rule for both of them. Exactly how would you use the chain rule for the first question?
7. ## Trig derivatives

Can someone help me on these two questions... you must find the first two derivatives of f(x)... first: f(x)= -cot(x) I think I've got the first one... f'(x)= csc^2(x) but I'm lost on the second derivative. Next Question: f(x)= sec(x) - csc(x) again, I think I've got the first one... f'(x)= sec(x)tan(x) + csc(x)cot(x) but f''(x)= ??? Thanks.
8. ## Can someone help with this limits question?

Here is the question: $\lim_{x\to\infty}\left(1+\frac{2}{x}\right)^x$ I thought that (1 + 2/x) as x approaches infinity is just 1... and 1 to the power of anything (including x) is still 1. But it turns out that 1 is the wrong answer. What's up with that?
9. ## continuity

Here is the question: f(x)= (x^2-36)/(x-6) for 0<x<6 and 2x for 6<x<12 How should f(6) be defined in order for f to be continuous? I originally said 'no limit' but apparantly that is wrong. The answer is actually 12... which is fine for the second equation because 2x=2*6=12... but I don't understand how the first equation could equal 12? If I replace x with 6 in the first equation I get 0/0 could someone help me out with this?
10. ## simple logarithm question

Can someone explain to me how to solve for x in this example? ln(x-2)=3 Also, is there a difference between ln, lg, and log or do they all mean the same thing? Thanks
11. ## Trig Identities via COW

Excellent, I got the question right. Thanks again Dave.
12. ## Trig Identities via COW

Thanks Dave, One more question... They give an identity for sin(2x) but not for sin(3x) One of their later questions is: put sin(3r) in terms of sin® How would I figure this one out?

14. ## Trig Identities via COW

Howdy. I've been working through this site called Calculus On the Web or COW. It's been a great site so far, but I have a question on the section entitled 'Trigonometric Identities' At the top of the page it shows the situation where x = cos a y = sin a Then at the bottom of the same page, in an example, it says that side B = tan a I don't understand this. In the example at the top, isn't side B = y coordinate = sin a how can side B = tan a? Unfortunately there is not a direct link to the page I'm talking about. You must go here : Calculus On the Web and then click on : Precalculus Book Functions Trigonometry Trig Identities Then click on 'HELP' at the bottom and the page I am discussing will come up. Thanks for any help
15. ## Best Sci-Fi Series

WooHoo, I broke the tie with the x-files... OTHER kicks butt!!! Especially season 3 episode 5! seriously though... Smallville Voyager V Buck Rogers
16. ## How did you find this site?

I used to go to a site called 'dr neutrino' or 'ask dr neutrino' this was, in my opinion, the best science forum on the web, but it shut down one day, and ever since, I have been searching for a science forum that measured up to it. None came close until I ran across this one. (Yahoo! Search)
17. ## Dividing complex numbers...

Duh. so the answer is 1/4 i Thanks.
18. ## Dividing complex numbers...

Thanks A lot! Here's another one that has to be put into the same form: x = -1/(4i) Any help appreciated.
19. ## Dividing complex numbers...

I am sure this is very simple, but could someone work through this question for me? This is not homework, I just want to learn the steps to do it. x = (4-i)/(1-3i) I am supposed to put it into the form x = a + bi The answer is: x = 7/10 - 11/10 i Thanks for any help you can give me.

21. ## simple relativity question

Yes.. using the length contraction equation, those are the answers I got. A= 39.2 m B= 91.9 m
22. ## What seems to be a simple question..

I will attempt an answer before the smart people get here... In the photons frame of reference, time is dilated infinitely, AND length is contracted infinitely so that the photon experiences it's entire travel in an instant. However, in any other frame of reference (ie a frame of reference that is not travelling at c), the photon is travelling at about 300,000km/s. So, from your frame of reference, light takes about 8 minutes to get from the sun to your eyeball. In the photons frame of reference, the trip from the sun to your eyeball is virtually instantaneous. I'm not sure, but I think some will argue about being able to talk about the photon's frame of reference. So: Yes, that's right. But only from the photon's frame of reference.
23. ## Gravity and length

I believe many interferometers are in operation today, that were built to detect gravitational waves, where the idea behind them is to measure the distance between 2 points. If a gravitational wave comes by, space will contract or expand, changing the distance between these two points, and setting off a bunch of bells and whistles that will mark the beginning of a huge party.
24. ## Pics of Individual atoms

I did not want to continue with this discussion in YT's thread, so I started a new one...

oops.
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