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A frustrated professor once claimed that if all the reports she had graded in her career were stacked on top of one another, they would reach from the Earth to the moon. Assume that an average report is the thickness of about 10 sheets of printer paper and use a single dimensional equation to estimate the number of reports the professor would have had to grade for her claim to be valid.

Short Answer

Expert verified
The professor would have had to grade approximately \(3.84 \times 10^{11}\) reports for her claim to be valid.

Step by step solution

01

Identify the Known Values

From the problem, we know that: 1. The distance from Earth to the moon is approximately 384,400 km (or \(3.84 \times 10^8\) meters for calculation purpose). 2. Thickness of one sheet of paper is usually about 0.1mm. Therefore, the thickness of 10 sheets, which is the thickness of a report, is about 1mm or \(1 \times 10^{-3}\) m.
02

Set up a Conversion Equation

We want to know the number of reports that would reach from Earth to the moon. This can be calculated using the formula: \(d = n \times t\) where d = total distance (from Earth to the moon), n = number of reports, and t = thickness of one report. We know the values of d and t, so we can plug them into the equation to solve for n.
03

Solve for the Number of Reports

Substituting the known values into the equation, we get: \(3.84 \times 10^8 = n \times (1 \times 10^{-3})\). To solve for n, we divide each side by \(1 \times 10^{-3}\), which gives: \(n = \frac{3.84 \times 10^8}{1 \times 10^{-3}} = 3.84 \times 10^{11}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Chemical Engineering Education
When it comes to chemical engineering education, one critical skill students must learn is problem-solving with a strong foundation in principles like dimensional analysis.

In our exercise, the problem seems deceptively simple, but it embodies the essence of what engineers do: converting knowledge into practical estimates or solutions. Through insight and creativity, future engineers are trained to tackle challenges ranging from the molecular level to massive industrial scales.

Teachers, like the professor in the exercise, often encourage students to visualize abstract concepts—like stacking reports to reach the moon—to reinforce understanding. Practical problems allow students to apply a variety of academic lessons such as mathematics, science, and data analysis to real-world situations.

Educational exercises often involve approximations and assumptions that mirror professional practices. Students learn to make educated guesses, use correct units, and interpret the magnitude of their solutions. Moreover, educators continuously search for innovative ways to engage students with hands-on experiences that cement theoretical knowledge into applied skills.
Problem-Solving in Chemistry
In chemistry, as well as chemical engineering, problem-solving often involves careful observations, well-thought-out hypotheses, and precise calculations. One such calculation fundamental to chemistry is dimensional analysis.

This technique helps in converting one unit of measure into another and ensures that equations are dimensionally consistent, meaning that the formula makes sense in terms of units.

Our exercise illustrates this with an everyday example: the thickness of paper in reports. Chemists and engineers often rely on such dimensional analysis to ensure that their chemical reactions, processes, or design specifications are calculated correctly.

For chemistry students, exercises like these not only test their mathematical skills but also teach them to be meticulous with units—a single mistake in unit conversion can lead to a disaster in a real-life chemical setup. As students develop these skills, they build their ability to think logically and methodically, layering knowledge to solve progressively more challenging problems.
Unit Conversion
Unit conversion is a fundamental aspect of many scientific problems and is particularly crucial in engineering and chemistry. It allows us to translate different measurements into a common system to compare, understand, and solve problems.

The problem provided is a classic example where unit conversion is necessary for the solution. By understanding that 1 millimeter is equal to \(1 \times 10^{-3}\) meters, students can bridge their real-world knowledge with scientific concepts.

Unit conversions often entail multiplying or dividing by factors of 10 (as seen with the SI system), making the calculations generally straightforward but requiring attention to detail. The key is to cancel out the unwanted units systematically to derive the required unit—a skill that students refine through practice and application in diverse situations.

Mastering unit conversions enables students to navigate problems across disciplines, from calculating the height of a stack of papers to more complex tasks like determining reaction yields or flow rates in industrial processes. It is a skill that once learned, becomes a valuable part of their intellectual toolkit.

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Most popular questions from this chapter

A waste treatment pond is \(50 \mathrm{m}\) long and \(25 \mathrm{m}\) wide, and has an average depth of \(2 \mathrm{m}\). The density of the waste is \(75.3 \mathrm{lb}_{\mathrm{m}} / \mathrm{ft}^{3}\). Calculate the weight of the pond contents in \(\mathrm{lb}_{\mathrm{f}},\) using a single dimensional equation for your calculation.

The daily production of carbon dioxide from an \(880 \mathrm{MW}\) coal-fired power plant is estimated to be 31,000 tons. A proposal has been made to capture and sequester the \(\mathrm{CO}_{2}\) at approximately \(300 \mathrm{K}\) and 140 atm. At these conditions, the specific volume of \(\mathrm{CO}_{2}\) is estimated to be \(0.012 \mathrm{m}^{3} / \mathrm{kg}\). What volume \(\left(\mathrm{m}^{3}\right)\) of \(\mathrm{CO}_{2}\) would be collected during a one-year period?

The doozy is defined as the unit of force required to accelerate a unit of mass, called the cuz, with the gravitational acceleration on the surface of the moon, which is one-sixth of the normal gravitational acceleration on earth. (a) What is the conversion factor that would be used to convert a force from the natural unit to the derived unit in this system? (Give both its numerical value and its units.) (b) What is the weight in doozies of a 3 -cuz object on the moon? What does the same object weigh in Lizard Lick, North Carolina?

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According to Archimedes' principle, the mass of a floating object equals the mass of the fluid displaced by the object. Use this principle to solve the following problems. (a) A wooden cylinder 30.0 cm high floats vertically in a tub of water (density \(=1.00 \mathrm{g} / \mathrm{cm}^{3}\) ). The top of the cylinder is \(13.5 \mathrm{cm}\) above the surface of the liquid. What is the density of the wood? (b) The same cylinder floats vertically in a liquid of unknown density. The top of the cylinder is \(18.9 \mathrm{cm}\) above the surface of the liquid. What is the liquid density? (c) Explain why knowing the length and width of the wooden objects is unnecessary in solving Parts (a) and (b).

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