11 Special Theory Of Relativity Grey

Topics

Theories of Relativity

● Galilean Relativity ● Newtonian Physics ● Albert Einstein ● Special Relativity

(Special Theory of Relativity) How come facts are relative while laws are absolute?

Galileo Galilei

Isaac Newton

Albert Einstein 2

Galilean Relativity

Galilean Relativity

Galilean tranformation of velocities 6 m/s

6 m/s 3 m/s

6 m/s

2 m/s

3 m/s

– 4 m/s

2 m/s – 6 m/s Æ – 4 m/s

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Newtonian Physics in the Galilean Relativity

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Newtonian Physics in the Galilean Relativity

7 m/s

Mechanics is the same for all inertial frames of reference. 0 m/s

Both are right. They are entitled to their own analyses in their respective frames of reference.

7 m/s

?

Who is right?

Galileo Galilei

Isaac Newton

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Newtonian Physics in the Galilean Relativity

Newtonian Physics in the Galilean Relativity

The Aether* Dispute

The Aether* Dispute

Is there an absolute frame of reference?

Is there an absolute frame of reference?

What if… NONE? * also “ether”

Sagnac experiment 7

* also “ether”

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Newtonian Physics in the Galilean Relativity

The Light Speed Problem

Albert Einstein: “Light is right”

Galilean transformation doesn’t work for light!

What will someone experience when riding along a photon?

Technical: The EM wave equation is NOT INVARIANT with Galilean transformation.` 9

“I don’t think the structure of the human skull is to be blamed for man’s inability to understand the concept of infinity. He would certainly be able to understand it if when young, and while developing his sense of perception, he were allowed to venture out into the universe.” – Mileva Maric

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Special Relativity

Special Relativity

Consequences of special relativity Relativity of simultaneity Time dilation Length contraction Doppler effect Velocity addition Inertia (mass and momentum) Ultimate speed limit c Energy-mass equivalence

Postulates: in all inertial frames of reference… ● all laws of physics are the same. ● the speed of light is always the same in vacuum.

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Special Relativity

Special Relativity

Consequence of special relativity

Consequence of special relativity

Relativity of simultaneity

Time dilation

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Special Relativity

Special Relativity

Consequence of special relativity

Consequence of special relativity

Length contraction

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Special Relativity

Special Relativity

Consequence of special relativity

Consequence of special relativity Velocity addition

Doppler effect

cruising at low speeds

cruising at 0.17c

*sound speed = 0.0000001c 17

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Special Relativity

Special Relativity

Consequence of special relativity

Consequence of special relativity

Inertia (mass and momentum)

Energy-mass equivalence

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Special Relativity

Consequence of special relativity Ultimate speed limit c

General Relativity Next meeting

“Information can only travel as fast as c.”

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Quiz (1/4 pc of paper) 1. Which of the following is fundamentally constant? (speed of light, mass, energy) 2. Which of the following features becomes larger and larger (infinite) as an object reaches the speed of light? (speed, mass, length) 3. Give one of the postulates of Einstein that enabled him to come up with the Special Theory of Relativity.

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