Recent content by Nitric

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    Photons - Trying to find distance

    It says 5 photons/sec in the question.
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    Photons - Trying to find distance

    1. The night-adapted eye can detect as few as several photons per second -- say five to be definite. Assuming that the pupil of the eye is 0.6 cm in diameter, from what distance would it be possible for the naked eye to detect a 60-W lightbulb? 2. I'm not sure which equation to use. In...
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    Time Dilation: Finding Velocity & Age Difference

    lol i figured it out by using v=d/t
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    Time Dilation: Finding Velocity & Age Difference

    I figured out the velocity, which is 0.9c. How do I find how much Bill aged during the time Abby was traveling?
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    Time Dilation: Finding Velocity & Age Difference

    1. Twins Abby and Billy separate. Abby travels at a uniform speed (except for the brief turn-around period) to a star 4.2 light years away and, upon returning, finds that she is 5.2 years younger than Bill. How fast was Abby traveling? By how much has Bill aged during the period Abby was...
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    Showing px-Et is invariant using Lorentz Transformations

    Damn. Well I honestly have no idea, kinda stuck on this problem
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    Showing px-Et is invariant using Lorentz Transformations

    p x E and t?
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    Showing px-Et is invariant using Lorentz Transformations

    1. Using the Lorentz Transformations, show that the quantity px - Et is invariant, where p and E are the momentum and energy, respectively, of an object at position x at time t. 2. px - Et 3. I needed help on starting the problem. Where should I begin?
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    Is superimposing three velocities possible?

    each of which is greater than c/3? can it work? edit: i mean superposing* in the title
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    Now it remains to be shown that A = B. I'll leave that to you.

    Okay my way isn't right, still stuck on this :|
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    Now it remains to be shown that A = B. I'll leave that to you.

    Okay I did what I said on the previous post and so far I have: c^4[x'^2 + (vt')^2] - (c^2t')^2 - (vx'^2) / c^4(1-v^2/c^2) What can I do now to move forward? I don't see anything else cancel out.
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    Now it remains to be shown that A = B. I'll leave that to you.

    I need a common denominator to start canceling things out right, or can I do it before? This is the part where my algebra isn't as fresh as it should be. To get the common denominator, I have to multiply the left equation by c^4 (top and bottom) and multiple the right equation by 1 (top and...
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    Now it remains to be shown that A = B. I'll leave that to you.

    I'm sort of stuck, my algebra isn't as fresh as I thought it would be. But am I on the right track though? http://img264.imageshack.us/img264/1081/1233176495203dl2.jpg ^ My work
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    Now it remains to be shown that A = B. I'll leave that to you.

    thanks a lot, i will get on this now :D
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    Now it remains to be shown that A = B. I'll leave that to you.

    so I would have (x'+vt'/sqrt(1-v^2/c^2)^2 - c^2(t' + vx'/c^2 / sqrt(1-v^2/c^2) and simplify it algebraically to x'^2 - c^2t'^2 ?
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