4. Momentum

About this Lecture

Lecture

In this mini-lecture we explore momentum. As we move through this mini-lecture we: (i) define momentum p as p = ms, where m is the mass and s is the speed; (ii) consider the relationship between force and momentum given by F = ∆p/∆t, which we found by rewriting the change in speed, ∆s = ∆v-∆u, in terms of it’s initial speed ∆u and final speed ∆v and rearranging the equation F = ma; and (iii) conclude that the force is the change in momentum, and thus with no forces present, momentum will not change.

Course

In this course, Professor David Berman (Queen Mary University of London) gives an introduction to mechanics at a GCSE level. In the first mini-lecture, we define distance, speed, and acceleration before looking at how they are related mathematically and graphically in distance versus time graphs and speed versus time graphs. In the second mini-lecture, we discuss Newton’s Three Laws of Motion. In the third mini-lecture, we explore gravity, weight, and the acceleration due to gravity (g). The fourth mini-lecture introduces momentum and the relationship between momentum and force. In the fifth mini-lecture, we go over an example that illustrates Newton’s Third Law.

Lecturer

David Berman is a Professor of Theoretical Physics at Queen Mary. His research interests include string theory and ideas in fundamental theoretical physics, including non-commutative geometry, black holes physics, and quantum gravity. He has contributed to the Radio 4 biography series Great Lives and the In Our Time podcasts, including Great Lives: Richard Feynman (2018), Great Lives: Galileo (2019), In Our Time: Emmy Noether (2019), and In Our Time: Paul Dirac (2020).