CK-12-Physics - Intermediate

http://www.ck12.org Chapter 22. The Special Theory of Relativity

toward the center. Einstein, however, is on the ground observing the child and sees that the pavement is sunken in
the middle and this is the reason the ball always rolls toward the center.

FIGURE 22.10

The sun warps space according to gen-

eral relativity.

To see the effect of mass warping space, see the link below.

http://demonstrations.wolfram.com/BendingOfLightByAStar/

For a recap of special relativity, the link below may be of assistance.

http://www.youtube.com/watch?v=KYWM2oZgi4E&feature=related

1. Postulates of Special Relativity

Postulate 1: The laws of physics have the same form in all inertial frames of reference.

Postulate 2: The speed of light in vacuum is constant in all inertial frames of reference.

2. Time dilation:

Clocks moving relative to an observer who assumes himself “at rest,” run more slowly compared to the clocks

in the “at rest” frame. Such a slowing of time is calledtime dilation. The transformation equation between

the two frames is given by

t= √tp

1 −vc^22

The timetpis the proper time (also called the lab or at rest frame).

3. Length contraction

Objects in motion with respect to a proper frame (or “rest frame”) of reference are contracted in the direction

of their motion. The length of the (moving) object as measured from the proper frame is given by

L=Lp

√

1 −v

2

c^2 whereLpis the length measured in the proper frame.