Finding tinfoil length from mass, thickness and width

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JUSTaROCK
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Homework Statement


Aluminum, which has a mass of 2.7 grams for each cubic centimeter of volume, can be rolled into thin sheets
which your grandparents probably called "tinfoil." If a lump of aluminum of mass 0.75 kg is rolled into such a
sheet 18 μm thick and 25 cm wide, approximately how long is this roll of "tinfoil?"



Homework Equations



v = m/p p = density
v = L * A
surface area of circle = 4pi(r)^2
area of circle = pi(r)^2


The Attempt at a Solution



I have spent a lot of time on this problem but i can't seem to get it right i do not know what to do with the width or the thickness. I have tried to play it off like the width is the diameter,(which seems possible), but i just don't know what to do i have been working on this problem for 2 days now and i can't figure out what to do with it, please help i have a final on this tomorrow and i see it a lot in the old exams so i would like to know how to approach it if the problem gives thickness and width.
 

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JUSTaROCK said:

Homework Statement


Aluminum, which has a mass of 2.7 grams for each cubic centimeter of volume, can be rolled into thin sheets
which your grandparents probably called "tinfoil." If a lump of aluminum of mass 0.75 kg is rolled into such a
sheet 18 μm thick and 25 cm wide, approximately how long is this roll of "tinfoil?"

Homework Equations



v = m/p p = density
v = L * A
surface area of circle = 4pi(r)^2
area of circle = pi(r)^2

The Attempt at a Solution



I have spent a lot of time on this problem but i can't seem to get it right i do not know what to do with the width or the thickness. I have tried to play it off like the width is the diameter,(which seems possible), but i just don't know what to do i have been working on this problem for 2 days now and i can't figure out what to do with it, please help i have a final on this tomorrow and i see it a lot in the old exams so i would like to know how to approach it if the problem gives thickness and width.

Think about the sheet of the foil before you roll it up. What shape is it?
 
rectangle? so find the area of it as a rectangle ok ha ha don't know why i never thought of that
 
JUSTaROCK said:
rectangle? so find the area of it as a rectangle ok ha ha don't know why i never thought of that

A rectangle yes, but you are interested in the volume since the density is mass over volume.