EINSTEIN INFO

Special relativity

BY ALBERT EINSTEIN

TWO POSTULATES

• First Postulaet: All laws of Physics are the same in all inertial reference frames
• Second Postulate: The speed of light, c, in empty space will always have the same value regardless of the motion of the source or observer.

TIME DILATION

LENGTH CONTRACTION

The stretching of time an obeject experiences as it approaches the speed of light

The shortening of length of an object as it approaches the speed of light

As speed increases, length in the direction of motion decreases. Lengths in the perpensicular direction do not change.

The relationship between the time to (call it the proper time) in the frame of reference moving with the clock and the time t measured by viewing the same clock in another frame of reference (call it the relative time)

RELATIVISTIC VELOCITY ADDITION

The frame of the ship has a different clock rate and distance measure, and the notion of simultaneity in the direction of motion is altered, so the addition law for velocities is changed.

v is the relative velocity between two observers, u is the velocity of an object relative to one observer, and u' is the velocity relative to the other observer.

This change is not noticeable at low velocities but as the velocity increases towards the speed of light it becomes important.

Made by Justine Daumar from 12 STEM 2