Topic 1 Time Dilation

(a) Explain qualitatively why moving clocks run slow.

(b) Show that the ratio of times in two frames of reference is given by

Topic 2 Length Contraction

(a) Explain qualitatively why moving meter sticks are short.

(b) Show that the ratio of legths in two frames of reference is given by

Topic 3 Mass and Energy

Explain qualitatively why a moving mass seems more massive according to

and how mass, even at rest is equivalent to some energy according to

Examples

Little Molly Modern's mother takes her to school in the morning and then takes the train to work. Molly's father, who works nights and also rides the train, usually gets in somewhat after Mrs. Modern leaves. If Mr. Modern's train is traveling at near the speed of light relative to Mrs. Modern's train, he sees her train as only 3/4 as long as if they were at rest relative to each other. How fast does he see her train as moving? If he sees his mass as 100 kg, how massive does he seem to his wife?

Textbook Problems