Hi All(adsbygoogle = window.adsbygoogle || []).push({});

My first post here and I'm sure it's going to be one of the easiest for you to answer.

I've just read Einstein's book on the theory of relativity and now I'm currently reading 'Why does e=mc^{2}(and why should we care)' by Brian Cox and Jeff Forshaw.

My Math isn't up to much but I have a inquisitive mind... I'm stumped by something rather basic and early on in this book.

On page 51/52(ish) - not 100% sure as I'm reading the Kindle version - there's the first bit of maths which seems to be getting to the Lorentz transformations starting from good old Pythagoras.

The authors get us to T^{2}= 1/ (c^{2}—υ^{2}) which is all good.

But then we get this:

Taking the square root of our equation above for T^{2}, and multiplying by 2, we find that 2T= 2/√c^{2}υv^{2}

I'm baffled by where the 'v' has come from. I thought it was a problem with the Kindle fonts first of all - the 'u' is printed in italics and the 'v' not, wasn't sure if they were the same thing - but I found a PDF of the book and it's the same in there.

Can someone walk me through this?

Thanks

Steve

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# B Cox and Forshaw: Why E=mc^2 - a proper newbie question

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