A student notes that the length of a 12-inch long ruler held by her teacher (who is moving relative to her) is the same as that of her meter stick (when oriented parallel to his ruler).
(a) Find their relative speed (assuming they are moving in a direction parallel to their respective sticks)?
(b) If the teacher takes 5 minute to write an email according to his watch, find how long did it take him to write it according to the student?