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Lesson 4: Relativistic Mass

Lesson 1: Relativity - What is it?

  1. Fermilab's Time Dilation Challenge.
  2. The Basics of Relativity (6 seconds)
  3. The Relativity Game - Challenge what you know!

Note: For Fermilab's Time Dilation Challenge and The Relativity Game, you need Shockwave. You may painlessly Download Shockwave here if you do not have it.

Lesson 2: Time Dilation

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the basketball analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Lesson 3: Length Contraction

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the pole and the barn analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Lesson 4: Relativistic Mass

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Show me the Proton Analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

Give me the Proton Analyogy?

Exploring how this affects our measurement of length.

With a mass of 3.2 x 10-27 kg the proton will accelerate at:

This means, that in one second, the earth will see the proton accelerate to:

Hey! Newton's 2nd Law and kinematics gives the same velocity as that observed!

This means that the earth's frame would see the proton travel:

d=( 256,000,000 m/s)(1 s)

d = 256,000,000 m

Bringing it back together:

We push a tiny proton and expect to see it travel 270,000,000 m in the 1.0 second after our push. Instead we see it travel at 0.85 c, which makes it travel 256,000,000 meters!

This is much less than the 270,000,000 meters we expected. It is less by 14,000,000 meters or 8700 miles!

Question:

The proton isn't acting as we predict. It is acting (more massive, less massive, as massive) as a proton at rest.

Show me how this ties in with Length Contraction and Time Dilation.

 

Lesson 4: Relativistic Mass

  1. The equation.
  2. Where does that come from?
  3. I still don't get it! Give me the Proton analogy.
  4. So what? There's an equation. How do I use the equation in the game?
  5. Practice Problems.
  6. Examples to aid your practice.

 


© Brian Wegley, 1998
Comments and suggestions can be sent by e-mail to
Brian Wegley of Glenbrook South High School..
This page last updated on 7/23/98.