S'identifier

Consider a system comprising several point masses. The coordinates of the center of mass for this system can be expressed as the summation of the product of each mass and its position vector divided by the total mass:

Equation1

Suppose the point masses are replaced with an extended object with uniformly distributed mass. The coordinates of the center of mass for this object can be obtained by replacing the point mass with the differential mass element and the summation with an integral in the equation for the center of mass:

Equation2

Consider a ring with uniform mass distribution M and radius R. The circular symmetry ensures that the center of mass is located at the ring's geometric center:

Equation1

Consider a coordinate system with its origin located at the center of the ring. Since the ring has a uniform mass distribution, the linear mass density is constant. So, the differential mass element on the surface of the ring is the product of the linear mass density and the differential length element on the ring's surface.

Now, using the expression for the center of mass and substituting the value of the position vector in the component form and the differential mass element gives the following equation:

Equation3

As the arc length ds subtends a differential angle , the arc length equals the radius multiplied by the differential angle. The linear mass density is the total mass divided by the length of the ring. Incorporating these values of arc length and linear mass density, the center of mass expression reduces to the following:

Equation4

The variable of integration is the angle θ. So, the limits of integration around the ring are θ = 0 to θ = 2π. The integral is separated into the x and y components and integrated across the limits:

Equation5

Since the origin of the coordinate is located at the center of the ring, the center of mass of the ring lies at its geometric center.

Tags

Gravitational Potential EnergyCenter Of MassExtended ObjectsPoint MassesUniform Mass DistributionRing Mass DistributionLinear Mass DensityDifferential Mass ElementArc LengthIntegration LimitsGeometric CenterCircular SymmetryCoordinate System

Du chapitre 9:

article

Now Playing

9.15 : Gravitational Potential Energy for Extended Objects

Quantité de mouvement, impulsion et collisions

1.3K Vues

article

9.1 : Quantité de mouvement

Quantité de mouvement, impulsion et collisions

13.4K Vues

article

9.2 : Force et quantité de mouvement

Quantité de mouvement, impulsion et collisions

13.7K Vues

article

9.3 : Impulsion

Quantité de mouvement, impulsion et collisions

16.8K Vues

article

9.4 : Théorème de la quantité de mouvement

Quantité de mouvement, impulsion et collisions

10.8K Vues

article

9.5 : Conservation de la quantité de mouvement : introduction

Quantité de mouvement, impulsion et collisions

14.2K Vues

article

9.6 : Conservation de la quantité de mouvement : résoudre les problèmes

Quantité de mouvement, impulsion et collisions

9.5K Vues

article

9.7 : Types de collisions - I

Quantité de mouvement, impulsion et collisions

6.4K Vues

article

9.8 : Types de collisions - II

Quantité de mouvement, impulsion et collisions

6.6K Vues

article

9.9 : Collisions élastiques : introduction

Quantité de mouvement, impulsion et collisions

10.7K Vues

article

9.10 : Collisions élastiques : cas d'étude

Quantité de mouvement, impulsion et collisions

11.6K Vues

article

9.11 : Collisions à plusieurs dimensions : introduction

Quantité de mouvement, impulsion et collisions

4.3K Vues

article

9.12 : Collisions à plusieurs dimensions : résoudre les problèmes

Quantité de mouvement, impulsion et collisions

3.4K Vues

article

9.13 : Centre d'inertie : introduction

Quantité de mouvement, impulsion et collisions

12.4K Vues

article

9.14 : Centre d'inertie : résoudre les problèmes

Quantité de mouvement, impulsion et collisions

6.1K Vues

See More

JoVE Logo

Confidentialité

Conditions d'utilisation

Politiques

Recherche

Enseignement

À PROPOS DE JoVE

Copyright © 2025 MyJoVE Corporation. Tous droits réservés.