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Chewy0087
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Homework Statement
sorry for another one of these threads...hopefully after this one i won't have to bug anyone else xS
http://www.physics.ox.ac.uk/admissions/undergraduate/admissions_test/tests08.pdf
page 6 - Question 23 - ONLY HELP WITH THE SECOND HALF I NEED, the 'SHOW THAT...' BIT IS FINE
Homework Equations
mass = A * thickness * density
The Attempt at a Solution
this is simply more of a checking thing, I know i should have more confidence and stuff and i know i find these threads annoying but i'd really appreciate just some confirmation that i have indeed got it right!
basically I did M = AdD (with m bieng mass and D bieng density)
rearranged to get d = [tex]\frac{M}{AD}[/tex]
Which i put in the Vmax equation giving me; Vmax = [tex]\frac{BM}{AD}[/tex]
I then proceeded to put that V max and d figures into the main equation giving me;
Emax = [tex]\frac{pA^2B^2M^2}{2mA^2D^2}[/tex] which i canceled to give me Emax = [tex]\frac{pB^2m}{2D}[/tex] is this correct? :F
the reason why I worry is that I put the numbers they give into the equation to give me;
Emax = [tex]\frac{2 * 10^-11 * 4 * 10^14}{2*10^3}[/tex] which cancels to give only 4J...
if that is correct what would that imply for the final question about it's practicality? i guess it would not be practical because it cannot store enough energy?
thanks for the help again guys!
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