Relativity

Question 1

What is proper length, l ?

Answer 1

Proper length is the length of an object measured in a reference frame in which the object is at rest.

Question 2

What is proper time?

Answer 2

Proper time is the time interval between two events measured in a reference frame in which the events occur at the same position.

Question 3

What is the time interval between events in a frame moving with relative velocity v?

Answer 3

t = t’