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Ch 42: Molecules and Condensed Matter
Young & Freedman Calc - University Physics 14th Edition
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610당신이 사용하는 게 아니라요?교과서 변경
42장, 문제 8

Two atoms of cesium (Cs) can form a Cs2Cs_2 molecule. The equilibrium distance between the nuclei in a Cs2Cs_2 molecule is 0.447 0.447 nm. Calculate the moment of inertia about an axis through the center of mass of the two nuclei and perpendicular to the line joining them. The mass of a cesium atom is 2.21×10252.21\(\times\)10^{-25} kg.

검증된 단계별 안내
1
Step 1: Understand the problem. The moment of inertia (I) for a diatomic molecule like Cs₂ is calculated about an axis through the center of mass and perpendicular to the line joining the two nuclei. The formula for the moment of inertia is I = μ * r², where μ is the reduced mass of the system, and r is the distance between the two nuclei.
Step 2: Calculate the reduced mass (μ). The reduced mass is given by the formula μ = (m₁ * m₂) / (m₁ + m₂), where m₁ and m₂ are the masses of the two cesium atoms. Since both atoms are identical, μ simplifies to μ = m / 2, where m is the mass of a single cesium atom.
Step 3: Convert the equilibrium distance (r) into meters. The given equilibrium distance is 0.447 nm. Convert this to meters by multiplying by 10⁻⁹, so r = 0.447 * 10⁻⁹ m.
Step 4: Substitute the values of μ and r into the formula for the moment of inertia. Use the expression I = μ * r², where μ is the reduced mass calculated in Step 2 and r is the equilibrium distance in meters from Step 3.
Step 5: Simplify the expression to find the moment of inertia. Ensure that the units are consistent (kg·m²) and that the calculation is performed correctly. The result will give the moment of inertia of the Cs₂ molecule about the specified axis.

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주요 개념

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Moment of Inertia

The moment of inertia is a measure of an object's resistance to changes in its rotational motion about a specific axis. It depends on the mass distribution relative to the axis of rotation. For two point masses, the moment of inertia can be calculated using the formula I = m * r^2, where m is the mass and r is the distance from the axis of rotation.
추천 영상:
가이드 코스
11:47
Intro to Moment of Inertia

Center of Mass

The center of mass is the point at which the mass of a system is concentrated and about which the mass is evenly distributed. For two identical masses, the center of mass lies exactly halfway between them. In the case of the Cs_2 molecule, the center of mass is crucial for calculating the moment of inertia as it defines the axis of rotation.
추천 영상:
가이드 코스
06:30
Intro to Center of Mass

Equilibrium Distance

The equilibrium distance is the distance between two atoms or molecules at which the potential energy is minimized, and the forces acting on them are balanced. In the context of the Cs_2 molecule, this distance (0.447 nm) is essential for determining the separation between the two cesium nuclei when calculating the moment of inertia.
추천 영상:
가이드 코스
10:13
Torque & Equilibrium
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교과서 질문

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