- #1

## Homework Statement

Gold, which has a density of 19.32 g/cm3, 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 with a mass of 3.872 g, is pressed into a leaf of 5.372 μm thickness, what is the area of the leaf?

**(b)**If, instead, the gold is drawn out into a cylindrical fiber of radius 2.300 μm, what is the length of the fiber?

## Homework Equations

d = m/v

v = pi * r^2 * L

v = l*w*h

## The Attempt at a Solution

d = m/v[/B]

[Part A]

1) 19.32 g / 1 cm^3 = 3.872g / v

v = 4.98967 cm^3

2) 5.372 micrometer * 1 cm / 10,000 micrometer

= 0.0005372 cm

3) 4.98967 cm^3 / 0.0005372 cm

= 9288 cm^2

4) 9288 cm^2 * 1 m^2 / 10,000 cm^2

= 0.9288 m^2

[part B]

1) 2.300 μm * 1 cm / 10,000 μm

= 0.00023 cm

2) v = pi * r^2 * L

Since v = 4.98967 cm^3 ...

4.98967 cm^3 = pi * (0.00023 cm)^2 * L

4.98967 cm^3 = 0.0000001662 cm^2 * L

L = 30022100 cm

3) 30022100 cm * 1 m / 0.01 cm

= 3,002,210,000 m

Are part A and B correct?

B seems totally wrong!