3. Gravity

About this Lecture

Lecture

In this mini-lecture, we explore gravity. In particular we: (i) define weight W as the force due to gravity, which is given by the equation W = mg, where m is the mass and g = 10 m/s² is the acceleration due to gravity; (ii) show that for an object falling under gravity it’s acceleration a is equal to g, which is independent of mass; and (iii) emphasise that while on Earth it can be hard to test the acceleration of objets due to gravity because of friction, such as air resistance, this experiment can be easily done on the Moon where there is no air resistance.

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).