Einstein's Postulates

• What is Galilean relativity?


  A type of relativity familiar at everyday speeds
• Why does an object's speed appear different in various reference frames?

  Because velocity, position, and time vary by frame
• If Person D travels at $4 \text{ m/s}$ and throws a ball at $2 \text{ m/s}$, what is the ball's speed in Person C's frame?


  $6 \text{ m/s}$
• How does the speed of the ball depend on the reference frame?

  It varies based on the observer's motion
• What does Galilean relativity state about Newton's laws of motion?

  • They are the same in all inertial frames
  • Space and time are fixed and absolute
• What happens to space and time when approaching the speed of light?

  They become relative and depend on the frame
• What is the result of adding velocities at speeds close to light?

  It can exceed the speed of light
• What is Einstein's first postulate of special relativity?

  The laws of physics are the same in all inertial frames
• What does it mean to be stationary in one's own reference frame?

  One cannot tell if they are moving
• What should the results of a physics experiment be on a moving train compared to a stationary platform?

  They should produce the same results
• What is Einstein's second postulate of special relativity?

  The speed of light is the same in all frames
• How do different observers measure the speed of light?

  They measure it as the same value, $c$
• If a runner holds a flashlight, how does their speed affect the light's speed?

  The speed of light remains $c$
• Why are Einstein's postulates important in special relativity?

  • They are conceptually significant
  • They are mathematically crucial for equations