/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 80 Suppose that a steel hoop could ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Suppose that a steel hoop could be constructed to fit just around the earth's equator at a temperature of \(20.0^{\circ} \mathrm{C}\) . What would be the thickness of space between the hoop and the earth if the temperature of the hoop were increased by 0.500 \(\mathrm{C}^{\circ} ?\)

Short Answer

Expert verified
The space between the hoop and Earth is approximately 35 meters.

Step by step solution

01

Understanding the Problem

We need to determine the expansion of a steel hoop that initially fits around Earth's equator after a 0.500°C temperature increase. This problem involves thermal expansion in physics, where dimensions of objects change with temperature.
02

Calculate Earth's Circumference

Earth's circumference can be approximated as \(2\pi R\) where \(R\) is Earth's average radius, about \(6,371\) km.
03

Calculate Initial Hoop Circumference

The initial circumference of the hoop is equal to Earth's circumference, \[C_{initial} = 2\pi \times 6,371,000\ m = 40,030,173\ m.\]
04

Calculate Thermal Expansion of Hoop

Use the formula for linear expansion, \(\Delta L = \alpha L_0 \Delta T\) where \(\alpha = 11\times10^{-6}\ 1/^{\circ}C\) is the coefficient of linear expansion for steel, \(L_0 = 40,030,173\ m\) is the initial length (circumference), and \(\Delta T = 0.500\ ^{\circ}C\) is the temperature increase.
05

Solve for Change in Hoop Circumference

Calculate the change in circumference: \[\Delta L = 11 \times 10^{-6} \times 40,030,173 \times 0.500 = 220.165\ m.\]
06

Calculate the Radius of Increased Hoop

Find the new radius using the expanded circumference \(C = 2\pi R_{new}= 40,030,173 + 220.165\ m\), solve for \(R_{new}\).
07

Find the Change in Radius

The thickness of space between the hoop and Earth is the difference in the new and original radii: \[R_{new} - R = \frac{220.165}{2\pi} \approx 35\ m.\]

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

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

Coefficient of Linear Expansion
The concept of the Coefficient of Linear Expansion is crucial in understanding how materials expand in response to temperature changes. This coefficient, denoted as \( \alpha \), measures how much a material's length will change per degree change in temperature. For steel, which is the material in question for the steel hoop, the coefficient \( \alpha \) is \( 11 \times 10^{-6} \ \/^{\circ}C \). This means for every degree Celsius increase in temperature, the steel will expand by a fraction of its original length, proportional to this coefficient. Knowing the coefficient allows engineers and scientists to predict how much a material will expand, which is essential for designing structures that must withstand temperature variations. The formula used to calculate the change in length due to thermal expansion is \( \Delta L = \alpha L_0 \Delta T \), where \( L_0 \) is the original length and \( \Delta T \) is the change in temperature.
Circumference Calculation
Circumference Calculation is a fundamental step when dealing with circular objects such as the steel hoop in this exercise. The circumference \( C \) of a circle is determined by the formula \( C = 2\pi R \), where \( R \) is the radius of the circle. In the problem, the initial circumference of the hoop equals Earth's circumference, because it fits snugly around the equator.

Calculating Earth's circumference involves using its average radius, approximately \( 6,371 \ km \) or \( 6,371,000 \ m \). Thus, the initial circumference of the hoop is \( 40,030,173 \ m \). Accurate calculation of circumference is key, as it forms the baseline for understanding how much the hoop expands after a temperature increase.
Temperature Change Effect
The Temperature Change Effect explains how changes in temperature impact the dimensions of materials. When the temperature of a material such as steel increases, the atoms in the steel move more vigorously, causing the material to expand. This is why, when the temperature of our hoop increases by \( 0.500 \ ^{\circ}C \), its circumference also increases.

The change in circumference \( \Delta L \) can be calculated using the formula \( \Delta L = \alpha L_0 \Delta T \), where \( \alpha \) is the coefficient of linear expansion, \( L_0 \) is the original circumference, and \( \Delta T \) is the temperature change.
The temperature change in this exercise leads to a \( 220.165 \ m \) increase in the hoop's circumference, illustrating how even a small increase in temperature can result in a significant dimensional change when dealing with large objects like the hoop.
Radius Calculation
Radius Calculation becomes necessary after determining how much the circumference changes due to thermal expansion. Once the new circumference of the hoop is known, calculating the new radius follows from the circumference formula \( C = 2\pi R_{new} \). The formula can be rearranged to solve for the new radius \( R_{new} = \frac{C}{2\pi} \).

In the exercise, the expanded circumference becomes \( 40,030,173 + 220.165 \ m \). Calculating the new radius inserted into this formula yields an increase in the radius. Finally, the gap between the Earth and the hoop, or the expansion space, is calculated as the difference between the new and original radii, resulting in approximately \( 35 \ m \). This gives us a full understanding of how the increase in the hoop's size translates into an increased radius and ultimately a space between the hoop and Earth.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The Sizes of Stars. The hot glowing surfaces of stars emit energy in the form of electromagnetic radiation. It is a good approximation to assume \(e=1\) for these surfaces. Find the radii of the following stars (assumed to be spherical): (a) Rigel, the bright blue star in the constellation Orion, which radiates energy at a rate of \(2.7 \times 10^{32} \mathrm{W}\) and has surface temperature \(11,000 \mathrm{K} ;\) (b) Procyon \(\mathrm{B}\) (visible only using a telescope), which radiates energy at a rate of \(2.1 \times 10^{23} \mathrm{W}\) and has surface temperature \(10,000 \mathrm{K}\) . (c) Compare your answers to the radius of the earth, the radius of the sun, and the distance between the earth and the sun. (Rigel is an example of a supergiant star, and Procyon \(\mathrm{B}\) is an example of a white dwarf star.)

Heat Loss During Breathing. In very cold weather a significant mechanism for heat loss by the human body is energy expended in warming the air taken into the lungs with each breath. (a) On a cold winter day when the temperature is \(-20^{\circ} \mathrm{C}\) , what amount of heat is needed to warm to body temperature \(\left(37^{\circ} \mathrm{C}\right)\) the 0.50 \(\mathrm{L}\) of air exchanged with each breath? Assume that the specific heat of air is 1020 \(\mathrm{J} / \mathrm{kg} \cdot \mathrm{K}\) and that 1.0 \(\mathrm{L}\) of air has mass \(1.3 \times 10^{-3} \mathrm{kg}\) . (b) How much heat is lost per hour if the respiration rate is 20 breaths per minute?

A carpenter builds an exterior house wall with a layer of wood 3.0 \(\mathrm{cm}\) thick on the outside and a layer of Styrofoam insulation 2.2 \(\mathrm{cm}\) thick on the inside wall surface. The wood has \(k=0.080 \mathrm{W} / \mathrm{m} \cdot \mathrm{K}\) , and the Styrofoam has \(k=0.010 \mathrm{W} / \mathrm{m} \cdot \mathrm{K}\) . The interior surface temperature is \(19.0^{\circ} \mathrm{C}\) , and the exterior surface temperature is \(-10.0^{\circ} \mathrm{C}\) (a) What is the temperature at the plane where the wood meets the Styrofoam? (b) What is the rate of heat flow per square meter through this wall?

Size of a Light-Bulb Filament. The operating temperature of a tungsten filament in an incandescent light bulb is 2450 \(\mathrm{K}\) , and its emissivity is 0.350 . Find the surface area of the filament of a \(150-\mathrm{W}\) bulb if all the electrical energy consumed by the bulb is radiated by the filament as electromagnetic waves. (Only a fraction of the radiation appears as visible light)

Two beakers of water, \(A\) and \(B\) , initially are at the same temperature. The temperature of the water in beaker \(A\) is increased \(10 F^{\circ},\) and the temperature of the water in beaker \(B\) is increased 10 \(\mathrm{K}\) . After these temperature changes, which beaker of water has the higher temperature? Explain.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.