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Lecture

Drag, Momentum, and Center of Mass

In course

PHYS-101(en): General physics : mechanics (English)

Students will learn the principles of mechanics to enable a better understanding of physical phenomena, such as the kinematics and dyamics of point masses and solid bodies. Students will acquire the capacity to quantitatively analyze these effects with the ...

Description

This lecture covers the concepts of drag, momentum, and center of mass. It starts by explaining resistive forces such as viscous drag and provides examples of laminar and turbulent drag. The conservation of momentum is discussed, emphasizing that the total momentum of an isolated system remains constant. The lecture also delves into impulse and momentum, defining impulse as the integral of a net force over time. The center of mass is introduced as the 'average' position of a system weighted by mass, and its kinematics are explored. The importance of applying forces at the center of mass is highlighted, along with the separation of internal and external forces. Various conceptual questions and demonstrations further illustrate these physical principles.

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Instructors (3)

Suliana Manley

From 2016 Associate professor, EPFL, Lausanne, Switzerland 2009-2016 Tenure-track assistant professor, EPFL, Lausanne, Switzerland 2006-2009 Post-Doctoral fellow, National Institutes of Health, Bethesda, MD, USA 2004-2006 Post-Doctoral fellow, Massachusetts Institute of Technology, Cambridge, MA, USA 1999-2004 PhD (Physics) Awarded 06/2004, Harvard University, Cambridge, MA, USA 1993-1997 Bachelors (Cum Laude) Physics & Mathematics, Rice University, Houston, TX, USA

Marcelo Baquero Ruiz

Justin Richard Ball

Official source

Ontological neighbourhood

Physics

Relativity: Special relativity

Related concepts (32)

Four-momentum

In special relativity, four-momentum (also called momentum–energy or momenergy) is the generalization of the classical three-dimensional momentum to four-dimensional spacetime. Momentum is a vector in three dimensions; similarly four-momentum is a four-vector in spacetime. The contravariant four-momentum of a particle with relativistic energy E and three-momentum p = (px, py, pz) = γmv, where v is the particle's three-velocity and γ the Lorentz factor, is The quantity mv of above is ordinary non-relativistic momentum of the particle and m its rest mass.

Center-of-momentum frame

In physics, the center-of-momentum frame (COM frame), also known as zero-momentum frame, is the inertial frame in which the total momentum of the system vanishes. It is unique up to velocity, but not origin. The center of momentum of a system is not a location, but a collection of relative momenta/velocities: a reference frame. Thus "center of momentum" is a short for "center-of-momentum ". A special case of the center-of-momentum frame is the center-of-mass frame: an inertial frame in which the center of mass (which is a single point) remains at the origin.

Angular momentum

In physics, angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity – the total angular momentum of a closed system remains constant. Angular momentum has both a direction and a magnitude, and both are conserved. Bicycles and motorcycles, flying discs, rifled bullets, and gyroscopes owe their useful properties to conservation of angular momentum.

Energy–momentum relation

In physics, the energy–momentum relation, or relativistic dispersion relation, is the relativistic equation relating total energy (which is also called relativistic energy) to invariant mass (which is also called rest mass) and momentum. It is the extension of mass–energy equivalence for bodies or systems with non-zero momentum. It can be written as the following equation: This equation holds for a body or system, such as one or more particles, with total energy E, invariant mass m0, and momentum of magnitude p; the constant c is the speed of light.

Invariant mass

The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, it is a characteristic of the system's total energy and momentum that is the same in all frames of reference related by Lorentz transformations. If a center-of-momentum frame exists for the system, then the invariant mass of a system is equal to its total mass in that "rest frame".

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