Concepts In Theoretical Physics - General Relativity

Concepts In Theoretical Physics - General Relativity -...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Concepts in Theoretical Physics David Tong Lecture 7: General Relativity
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gravity is Geometry
Background image of page 2
Inertial and Gravitational Mass s Mass arises in two different formulae, both due to Newton b Gravitational Mass: b Inertial Mass: s Yet the meaning of mass in these two formulae is very different. F = ma F = GmM/r 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Inertial and Gravitational Mass s Mass arises in two different formulae, both due to Newton b Gravitational Mass: b Inertial Mass: s Yet the meaning of mass in these two formulae is very different. s We should really distinguish between the two masses by calling them something different. F = m I a F = Gm G M G /r 2
Background image of page 4
Inertial and Gravitational Mass s Mass arises in two different formulae, both due to Newton b Gravitational Mass: b Inertial Mass: s Yet the meaning of mass in these two formulae is very different. s We should really distinguish between the two masses by calling them something different. s Experimentally, we find F = m I a F = Gm G M G /r 2 m I = m G To an accuracy of 1 part in 10 13
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Inertial and Gravitational Mass s The equality of inertial and gravitational mass is responsible for the well known fact that objects with different mass fall at the same speed under gravity. s According to legend, this was demonstrated by Galileo dropping farm animals from the leaning tower of Pisa. s But is there a deeper reason why the gravitational force is proportional to the inertial mass?
Background image of page 6
s There are two other forces which are also proportional to the inertial mass. These are b Centrifugal Force: b Coriolis Force: s But in both of these cases, we understand very well why the force is proportional to the inertial mass, m. It follows because these are “fictitious forces”, arising in a non-inertial frame. (In this case, one that is rotating with frequency ) s Could gravity also be a fictitious force, arising only because we are in a non-inertial frame? The answer, of course, is yes! F
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 21

Concepts In Theoretical Physics - General Relativity -...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online