Special and General Relativity: Key Concepts and Black Holes

What is NOT a consequence of the postulates of special relativity?

The wavelength emitted from a source moving with respect to an observer is different from the wavelength measured by an observer who is moving along with the source.

Which statement about the clock as seen by you is NOT correct?

The clock will appear thinner, front to back, than it would if it were at rest.

Why does Einstein's theory of special relativity carry the name special?

The theory deals only with objects moving in a straight line at a constant speed.

How must an object be moving for us to use the theory of special relativity?

The object must be moving at a constant speed in a straight line.

If you see an object moving past you at 90% of the speed of light, how will its length appear?

The object will look shorter than if it were at rest.

if you stay on Earth while a friend races off in a rocket at a speed close to the speed of light,
then according to special relativity you will see a clock on the rocket appear to tick more slowly
than the one on your wall. If your friend looks back at your clock, then according to the same
theory the friend will see your clock appear to tick

slower than the clock on the rocket

What will your friend see about your clock while moving in a rocket?

Your friend will see your clock appear to tick slower than the clock on the rocket.

Einstein’s theory of special relativity contains some very strange ideas such as time dilation
(moving clocks run slow), length contraction (moving lengths are shorter), and lack of absolute
simultaneity. What is the basis of these ideas?

The speed of light is the same for all observers in all reference frames.

How does classical physics describe the fabric of space and time?

Space is perfectly uniform, and time passes at a uniform rate for all observers.

How is the general theory of relativity more general than the special theory?

The general theory includes gravitation and accelerated motion.

How does a gravitational field affect the passage of time?

Clocks in a gravitational field run slower than clocks farther from the center of the field.

What happens to a clock that ticks at a regular rate far from gravity?

It will appear to tick slower as it comes closer to the source of gravity.

In a binary star system, one component is found to have about 3 solar masses, the other about 7
solar masses. The 3-solar-mass star is visible from Earth, but the 7-solar-mass star is not.
Theoretical considerations tell us that the 7-solar-mass star must be a

a black hole.

In the context of black holes, what is a singularity?

A place where a nonzero mass occupies zero volume.

What is the event horizon of a black hole?

The surface from inside of which nothing can escape.

What happens if you pass through the event horizon of a black hole?

You could do nothing to prevent yourself from falling directly into the singularity.

What is the Schwarzschild radius of a black hole?

The distance from the black hole's singularity to the point where nothing can escape.