Classical Mechanics (MEC_2F001)

Ce cours traite des référentiels non inertiels et des forces fictives, des formulations lagrangienne et hamiltonienne, ainsi que de la mécanique du solide rigide. Il explore des notions telles que les champs de vitesses, la décomposition de l'énergie cinétique, le moment cinétique et les lois de conservation. Se fondant sur le calcul des variations, la mécanique lagrangienne est présentée comme un principe variationnel pour les systèmes contraints, tandis que la mécanique hamiltonienne met l'accent sur la conservation de l'énergie et son rôle en physique quantique. Parmi les exemples pratiques abordés en cours figurent les tables tournantes, le pendule de Foucault et les disques roulants. Le cours allie rigueur mathématique et interprétation physique. Il suppose la connaissance préalable de la mécanique newtonienne et le calcul vectoriel. À l'issue du cours, les étudiants maîtriseront les techniques mathématiques fondamentales utilisées en physique et en mécanique, et auront découvert des phénomènes physiques ludiques.

At the end of the course, the students will understand how to obtain, in a given system, wave solutions if they exist, and how to characterize a family of waves. The illustrations, for acoustic waves and for geophysical waves, will have introduced general culture elements regarding music and musical  instruments, and certain oceanic and atmospheric motions.

The course describes waves in fluids, with a preference for illustrations coming from the Earth system, in particular the atmosphere and ocean. Waves are one essential type of motion present in many fluids. One goal of the course is to demonstrate how one proceeds to obtain wave solutions starting from a physical description of a system and its equations of motion. Acoustic waves will be considered as a first example, surface water waves at different scales (from ripples in the pond to tsunamis) will be derived as further examples. Basics of fluid mechanics (Euler equations, kinematics) will be introduced in order to make these developments possible. Similarities in the behavior of fluid waves and optical waves seen in PHY202 will be discussed.

At the end of the course, the students will understand how one characterizes a family of waves (dispersion relation, polarisation relations), and how to proceed to obtain, in a given system, wave solutions if they exist. Some preliminary considerations for exploring behaviors beyond linearity will have been introduced, as an opening. Finally, some elements of the study of the Earth, and of the atmosphere in particular, will have been introduced.