Level 194
Level 196

#### 26 words 0 ignored

Ready to learn
Ready to review

## Ignore words

Check the boxes below to ignore/unignore words, then click save at the bottom. Ignored words will never appear in any learning session.

**Ignore?**

Space-time

A combination of space and time, which are viewed in special relativity as two parts of one whole

special theory of relativity

Comprehensive theory of space and time that replaces Newtonian mechanics when velocities are very large; introduced in 1905 by Albert Einstein.

Postulates

fundamental assumptions

First postulate of special relativity

Object can measure its speed relative to other objects

Second postulate of special relativity

Speed of light in the vacuum will have the same value regardless of the motion of the source/observer

Time Dilation

Moving clocks run slow

Length contraction

L=L_0/γ, contraction is parallel to direction of motion

True

Mechanical waves require a medium to travel thru.

The flashes move along a diagonal path

A moving space ship contains a light clock. An observer is at rest with

30000

Traveling at the speed of light, how long would it take a person to reach

Relativistic Length Contraction stated mathematically

L=L(at rest) x Radical 1- (v^2/c^2)

t = t0(proper time) / (radical) 1- (v/c)^2

The equation for the relationship between the time t0 (proper

Equivalence Principle

It is impossible to distinguish between gravitational and inertial effects.

frame of reference

A set of rulers and synchronized clocks at every point in space (and at rest with respect to each other) that are used by observers who are at rest in the frame to record…

Gamma Factor (Lorentz factor)

The quantity γ=1/(√(1-v^2/c^2)) Gamma is always bigger than 1, but becomes appreciably bigger than 1 only for speeds larger than 0.5c.

Hafele-Keating experiment

An experiment in which clocks taken on board a fast-moving plane differed from similar clocks left behind when they were returned and compared. Provides evidence for time dilation.

Inertial Observer

An observer who is not accelerating.

Michelson-Morley experiment

An experiment designed to measure the speed of the earth relative to the ether. No such velocity was measured --and this led to the abandonment of the ether idea.

Muon decay experiments

According to Galilean relativity, muons created in the upper atmosphere should not arrive on the surface of the earth because their lifetime is short and they would have decayed.

Newtonian Limit

At low speeds, results of relativity and those of Newtonian mechanics agree,

Postulates of special relativity

(1)the speed of light in a vacuum is the same for all inertial observers. (2) the laws of physics are the same for all inertial observers.

Proper Length

the length of an object in its rest frame. It is the greatest length measure by any inertial observer.

Proper Time interval

The time interval between two events at the same point in space. It is the shortest time interval between the events measured by any inertial observer.

Rest Frame

The frame of reference in which a given object is at rest.

simultaneity

Occurring at the same time. In special relativity, two events that are simultaneous in one frame of reference need not be simultaneous in a frame moving relative to the first frame.

velocity addition

If frame A has velocity u with respect with frame B and frame B a velocity v with respect to time.