Chapitre 9
Quantité de mouvement, impulsion et collisions
Quantité de mouvement
The term momentum is used in various ways in everyday language, most of which are consistent with the precise scientific definition. Generally, momentum ...
Force et quantité de mouvement
Force and momentum are intimately related. Force acting over time can change momentum, and Newton's second law of motion can be stated in its most ...
Impulsion
According to Newton’s second law of motion, the rate of change of the momentum of an object is the net external force acting on it. The total change ...
Théorème de la quantité de mouvement
The total change in the motion of an object is proportional to the total force vector acting on it and the time over which it acts. This product is called ...
Conservation de la quantité de mouvement : introduction
The total momentum of a system consisting of N interacting objects is constant in time or is conserved. A system must meet two requirements for its ...
Conservation de la quantité de mouvement : résoudre les problèmes
Solving problems using the conservation of momentum requires four basic steps:
Identify a closed system, where the total mass is constant, and no net ...
Types de collisions - I
When two objects come in direct contact with each other, it is called a collision. During a collision, two or more objects exert forces on each other in a ...
Types de collisions - II
When two or more objects collide with each other, they can stick together to form one single composite object (after collision). The total mass of the ...
Collisions élastiques : introduction
An elastic collision is one that conserves both internal kinetic energy and momentum. Internal kinetic energy is the sum of the kinetic energies of the ...
Collisions élastiques : cas d'étude
Elastic collision of a system demands conservation of both momentum and kinetic energy. To solve problems involving one-dimensional elastic collisions ...
Collisions à plusieurs dimensions : introduction
It is far more common for collisions to occur in two dimensions; that is, the initial velocity vectors are neither parallel nor antiparallel to each ...
Collisions à plusieurs dimensions : résoudre les problèmes
In multiple dimensions, the conservation of momentum applies in each direction independently. Hence, to solve collisions in multiple dimensions, we should ...
Centre d'inertie : introduction
Any object that obeys Newton's second law of motion is made up of a large number of infinitesimally small particles. Objects in motion can be as ...
Centre d'inertie : résoudre les problèmes
The center of mass of an object is defined as the mass-weighted average position of all the particles that comprise the object. The significance of the ...
Énergie potentielle gravitationnelle pour les objets étendus
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 ...
Propulsion d'une fusée dans l'espace - I
The driving force for the motion of any vehicle is friction, but in the case of rocket propulsion in space, the friction force is not present. The motion ...
Propulsion d'une fusée dans l'espace - II
The motion of a rocket is governed by the conservation of momentum principle. A rocket's momentum changes by the same amount (with the opposite sign) ...
Propulsion d'une fusée dans un champ gravitationnel - I
Rockets range in size from small fireworks that ordinary people use to the enormous Saturn V that once propelled massive payloads toward the Moon. The ...
Propulsion d'une fusée dans un champ gravitationnel - II
A rocket's velocity in the presence of a gravitational field is decreased by the amount of force exerted by Earth's gravitational field, which ...
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