
#1
Aug2607, 01:02 PM

P: 23

1. The problem statement, all variables and given/known data
Gold, which has a density of 19.32 g/cm^3, is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber. (a) If a sample of gold, witha mass of 27.63g, is pressed into a leaf 1.000 µm thickness, what is the area of the leaf? (b) If, instead, the gold is drawn out into a cylindrical fiber of radius 2.500 µm, what is the length of the fiber? 2. Relevant equations ρ=m/V (density) 3. The attempt at a solution Im having trouble finding a direction to go in. I think converting to density is the way to go but I am having trouble using the density formula as well. 



#2
Aug2607, 01:11 PM

P: 1,295

Hint: You need to know volume of a cylinder, and that other thing (cube ?) in order to solve this. So, I guess both require two steps. 



#3
Aug2607, 02:23 PM

P: 23





#4
Aug2607, 02:27 PM

P: 1,295

Finding area of a gold leaf
first find the relationship between area and volume
and then between volume and density/mass and you will get the area 



#5
Aug2707, 07:55 AM

P: 23

I got it. Thanks for the help the relationship is what I was confusing but all I had to do was divde the density by the mass to get rid of the grams and then convert the cm^3 to µm^3 and relate the area and volume as you said and then the volume with the area.
Thanks 



#6
Jan2709, 03:22 PM

P: 12

How to solve this problem after finding volume using density and mass




#7
Jan2709, 04:01 PM

Sci Advisor
HW Helper
PF Gold
P: 3,725





#8
Jan2709, 06:52 PM

P: 12

Thanks for replaying back. 



#9
Jan2809, 02:14 PM

Sci Advisor
HW Helper
PF Gold
P: 3,725

Using the example of the gold leaf, assume you have a collection of finite elements, each of which is a cube of the same dimension as the thickness (w= 1.000 µm) of the foil. The area of each face of the cube will be w^{2} and you need two of 'em. Next, you need to understand that the total volume of the gold will be N*w^{3} where 'N' is equal to the number of elements of dimension w X w X w.
Can you get there from here? 


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