Worksheet 7, Section 102: Thermal Expansion And Energy Trans

Worksheet 7 Section 102thermal Expansion And Energy Transfer

Worksheet 7- Section 10.2 Thermal Expansion and Energy Transfer 1. Two identical metal rods are at room temperature. One rod is heated by 10 °C, and the other is cooled by 10 °C. How do their new lengths compare? 2. Which exchange process carries thermal energy through boiling water as it heats on top of a stove? 3. Does thermal energy exchange by radiation require a medium (particles of matter) through which the energy is transferred? 4. If you want to exchange a lot of thermal energy by conduction, should you use a conductor or an insulator? For Problems 5-7, refer to Table 10.1 for the coefficients of thermal expansion. 5. A hole in a copper plate has a diameter of 1.325 cm at 21.00 °C. What is the diameter of the hole at 224.0 °C? 6. A hole in a steel plate has a diameter of 1.166 cm at 23.00 °C. At what temperature is the diameter of the hole equal to 1.164 cm? 7. An aluminum rod changes its length by 0.0032 cm when the temperature changes by 120 °C. What was the initial length of the aluminum rod? Research Project GEB3213 How to research consumer and company financial information on Government websites The objective of this assignment is for you to acquire knowledge and skills on what consumer and company financial information is available from various government agencies and how to research the available information and data. You have been assigned a project by your employer to write a paper on how to research consumer and company financial information on Government websites. The parameters for the paper are: · Between words long excluding Works Cited or Bibliography · In APA format Your paper must report on any four of the following government agencies: · Bureau of Economic Analysis (BEA) · Bureau of Labor Statistics (BLS) · Commodity Futures Trading Commission · Consumer Financial Protection Bureau · Federal grants (grants.gov) · Federal Reserve Economic Data (FRED) · Government Accounting Office (GAO) · Securities and Exchange Commission (SEC) · Small Business Administration (SBA) You may substitute one agency with an agency of your choice, which must be approved by me. See A-Z Index of U.S. Government Departments and Agencies at (Links to an external site.) Your report must include the following: · Agency’s mission and responsibilities · History of agency (short; one paragraph) · What data is available to the public? · In what form is the data available? · How can the data be accessed by the public? · Who is the primary user of the data? · Why is the data accessed – for what purpose? · How current is the data. · What periodic reports are issued by the agency and frequency of those reports. · In addition, any other topics you believe relevant to your chosen career or current employment. How to cite a government website in APA format: Using American Psychological Association (APA) style is fairly easy. Only four elements must be obtained to cite a web page: author, date, title and source. If the format of the website is unusual, you may also need to include a format description in brackets in between title and source information. In-text citation follows standard author and page formats. Usually there is no page number, so just citing the author is common practice. An example looks like: Lee, Jessie. (2011, March 2). President Obama on the Tragic Events in Germany [Blog Post]. Retrieved from If no date is available, insert "n.d." instead. Read more:

Paper For Above instruction

Thermal expansion and energy transfer are fundamental concepts in physics that explain how materials respond to temperature changes and how energy moves through different media. This paper discusses key principles of thermal expansion, the mechanisms of energy transfer, and how these phenomena are relevant in practical and industrial contexts.

Thermal Expansion in Metals

Thermal expansion refers to the tendency of materials to change in size when their temperature varies. In metals, atoms are arranged in a crystalline structure, and as temperature increases, atoms vibrate more vigorously, causing the metal to expand. When the temperature decreases, atomic vibrations lessen, leading to contraction. The magnitude of expansion depends on the coefficient of thermal expansion specific to each material. For instance, a copper plate with a hole of 1.325 cm at 21.00°C will experience an increase in the diameter of the hole at higher temperatures. Using the coefficient of thermal expansion for copper, the change can be calculated by Δd = d × α × ΔT, where α is the coefficient for copper, and ΔT is the temperature change. Specifically, the hole's diameter at 224.0°C would increase significantly, affecting the fit and mechanical properties of components in engineering applications.

Energy Transfer Mechanisms

Energy transfer in thermodynamics occurs through three primary mechanisms: conduction, convection, and radiation. Conduction involves direct contact between molecules, allowing energy to flow from a higher temperature region to a lower one. Metals are good conductors because of their free-moving electrons, facilitating efficient heat transfer. When considering boiling water on a stove, energy is primarily transferred by conduction from the stove to the pot and by convection within the water. Convection involves the movement of fluid particles, carrying heat away from the heat source. Radiation, on the other hand, involves electromagnetic waves and can transfer energy through a vacuum, requiring no medium. For example, the Sun’s radiation reaches Earth through space without a medium, illustrating radiation’s medium-independent nature.

Practical Applications and Relevance

Understanding thermal expansion is vital in designing structural components such as bridges, railways, and pipelines, where temperature fluctuations could cause expansion and contraction. Engineers incorporate expansion joints and allowances to prevent damage due to thermal stresses. Recognizing the energy transfer mechanisms is equally crucial in thermal management systems, climate control, and energy efficiency improvements. For instance, insulating materials reduce heat loss by minimizing conduction and convection, while reflective surfaces minimize radiative heat transfer. Additionally, the coefficients of thermal expansion are essential in selecting appropriate materials for high-temperature environments to prevent material failure.

Problems and Calculations

Based on the data provided for thermal expansion, several calculations illustrate these principles. For example, the diameter of a hole in a copper plate at 224.0°C, starting at 1.325 cm at 21.00°C, can be estimated using the thermal expansion coefficient for copper, approximately 16.5 × 10⁻⁶ /°C (Callister & Rethwisch, 2014). The change in diameter Δd = 1.325 cm × 16.5 × 10⁻⁶ /°C × (224.0 - 21.00)°C results in an expanded hole size. Similarly, for steel and aluminum, their respective coefficients allow for calculating the respective diameter changes and initial lengths as per the problem statements. These calculations highlight key considerations in engineering design to accommodate thermal effects.

Conclusion

Thermal expansion and energy transfer phenomena are critical factors in the design, operation, and safety of engineering systems. Accurate understanding and application of these principles ensure structural integrity and energy efficiency. Ongoing research into material properties and thermal behaviors continues to improve technological advances and industrial processes, emphasizing the importance of mastering these fundamental concepts.

References

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