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V is multiplied by

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Master | Next Rank: 500 Posts
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by ST » Wed Jun 10, 2009 7:05 am
In the formula V = 1/(2r) ^3 , if r is halved, then V is multiplied by

a. 64
b. 8
c. 1
d. 1/8
e. 1/64

Answer is b

I just do not understand the explnation in the book. Could someone simplify this question for me?

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by tohellandback » Wed Jun 10, 2009 7:13 am
V = 1/(2r) ^3

if r is halved
1/(2r/2) ^3=8*1/(2r) ^3=8V
The powers of two are bloody impolite!!
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by ST » Wed Jun 10, 2009 7:32 am
yes, but how is it equal to 8V, just wondeing......:(
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by tohellandback » Wed Jun 10, 2009 7:37 am
dude just replace 1/(2r) ^3 with V in the final term.

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The powers of two are bloody impolite!!
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by Osirus@VeritasPrep » Wed Jun 10, 2009 9:22 am
Can someone explain why

1/(2r/2)^3 = (8) * 1/(2r/2)^3
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by tohellandback » Wed Jun 10, 2009 9:24 am
hey its not
1/(2r/2)^3 = (8) * 1/(2r/2)^3
it is
1/(2r/2)^3 = (8) * 1/(2r)^3
The powers of two are bloody impolite!!
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by Osirus@VeritasPrep » Wed Jun 10, 2009 9:45 am
Thanks
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