A5 Relativity Vocab

Front

What is a Reference Frame?

Back

A coordinate system used by an observer to measure the position, time, and motion of events.

Front

What is an Inertial Reference Frame?

Back

A reference frame that is not accelerating (moving at constant velocity). Newton's Laws hold true in these frames.

Front

What is Galilean Relativity?

Back

The principle that the laws of mechanics are the same in all inertial reference frames. (It breaks down at high speeds, >0.4c).

Front

What is the First Postulate of Special Relativity?

Back

The laws of physics are the same in all inertial reference frames.

Front

What is the Second Postulate of Special Relativity?

Back

The speed of light in a vacuum (c) is the same for all inertial observers.

Front

What is the Lorentz Factor (γ)?

Back

Front

What is Time Dilation?

Back

The phenomenon where a moving clock runs slower than an identical clock in the observer's rest frame.

Front

Back

The time interval between two events measured by an observer who is at rest relative to the events.

Front

What is Length Contraction?

Back

The phenomenon where the length of an object is measured to be shorter when it is moving relative to the observer.

Front

Back

The length of an object measured by an observer who is at rest relative to the object.