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Ch 12: Fluid Mechanics
Chapter 12, Problem 12

Gold Brick.You win the lottery and decide to impress your friends by exhibiting a million-dollar cube of gold. At the time, gold is selling for $1282 per troy ounce, and 1.0000 troy ounce equals 31.1035 g. How tall would your million-dollar cube be?

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Calculate the total mass of gold you can buy with a million dollars. First, determine how many troy ounces of gold you can purchase by dividing the total amount of money ($1,000,000) by the price per troy ounce ($1282).
Convert the total mass of gold from troy ounces to grams. Since 1 troy ounce is equal to 31.1035 grams, multiply the number of troy ounces by 31.1035 to get the mass in grams.
Determine the volume of the gold using its mass and the density of gold. The density of gold is approximately 19.32 g/cm^3. Use the formula for volume, V = mass/density.
Since the gold is in the shape of a cube, all sides are equal. The volume of a cube is given by V = s^3, where s is the side length. Solve for s by taking the cube root of the volume.
The result from the previous step gives the height of the cube in centimeters. This is the height of your million-dollar gold cube.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Density of Gold

Density is a measure of mass per unit volume, and for gold, it is approximately 19.32 g/cm³. This property is crucial for determining the volume of the gold cube based on its mass. By knowing the density, we can calculate how much space the gold occupies, which is essential for finding the dimensions of the cube.
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Volume of a Cube

The volume of a cube is calculated using the formula V = a³, where 'a' is the length of one side of the cube. To find the height of the cube, we need to determine the total volume of gold represented by the million-dollar value and then extract the cube root of that volume to find the height.
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Conversion of Units

In this problem, converting between different units is essential, particularly from troy ounces to grams and then to cubic centimeters. Understanding how to perform these conversions accurately ensures that all measurements are consistent, allowing for correct calculations of mass, volume, and ultimately the dimensions of the gold cube.
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Related Practice
Textbook Question
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A cubical block of wood, 10.0 cm on a side, floats at the interface between oil and water with its lower surface 1.50 cm below the interface (Fig. E12.33). The density of the oil is 790 kg/m^3. (a) What is the gauge pressure at the upper face of the block? (b) What is the gauge pressure at the lower face of the block? (c) What are the mass and density of the block?

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Textbook Question
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Textbook Question
BIO. Artery Blockage. A medical technician is trying to determine what percentage of a patient's artery is blocked by plaque. To do this, she measures the blood pressure just before the region of blockage and finds that it is 1.20×10^4 Pa, while in the region of blockage it is 1.15×10^4 Pa. Furthermore, she knows that blood flowing through the normal artery just before the point of blockage is traveling at 30.0 cm/s, and the specific gravity of this patient's blood is 1.06. What percentage of the cross-sectional area of the patient's artery is blocked by the plaque?
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Textbook Question
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