8.01x - Lect 7 - Weight, Weightlessness in Free Fall, Weight in Orbit
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it when a question turns on how weight is defined, since Lewin treats weight as the force you feel rather than simply the gravitational force.
Recommended by 1 people across 2 different months, 2018 to 2022.
What it is
Lecture 7 of Walter Lewin's MIT 8.01 classical mechanics course. He discusses weight as perceived gravity, weightlessness in free fall, and why astronauts in orbit are not really in zero gravity, with live demonstrations.
What people said
Recommends M. Enns · 2020-12 · Physics Stack Exchange · on “Weight in Newtonian mechanics”
Defining weight as simply a synonym for "force of gravity acting on an object" is very common but it is not the only way to define weight as Professor Walter Lewin explains in this lecture [this video] .
Recommends M. Enns · 2022-02 · Physics Stack Exchange · on “What is actually weight?”
The answer to this question depends on who you ask. A lot of people would say the weight of the book is just another way of saying the force of gravity that the Earth exerts on the the book but not everyone - see this lecture [this video] by Prof. Walter Lewin.
Cites Farcher · 2018-12 · Physics Stack Exchange · on “What's the difference between gravitational attraction and weight?”
This is an interesting question in that many scientists will say there is no difference but others, including Walter Lewin in this lecture [this video] would disagree.
Cites azeem sha · 2020-09 · Physics Stack Exchange · on “Weightlessness during free fall and in free space, are they same?”
Einstein's thought of a person under free-fall and when suspended in free space with no forces acting, will feel the same way. On Walter lewin's lecture [this video] on free fall he told free fall is when only gravity force is acting on a body (Newtonian Mechanics). How is these two thoughts connect, how both the conditions are same, one has a net force acting other has no net force. If we have to design a component/machine to work under these conditions, do we have to consider any forces, if so, which force. Edit: Improved understanding There is no force of gravity, when a body is in free space, the space-time is flat, in a gravity field its curved, a body placed in both will follow a geodesic p
Cites Farcher · 2022-02 · Physics Stack Exchange · on “What is actually weight?”
There seem to be at least two schools of thought. In terms of attraction in a gravitational field One definition of the weight of a body is the gravitational attraction on a body and so weight equal to $mg$ where $m$ is the mass of the body and $g$ is the gravitational field strength. With this definition weight varies only in so far as the gravitational field strength, on Earth $g = 9.8 \,\rm m/s^2$ approximately, varies. When you and the scales are accelerating, the scales are reading your apparent weight. When you are orbiting the Earth you appear to be weightless although you must still have a weight otherwise there would not be a force present causing the centripetal acceleration to kee