A student notes that the length of a 12-in.-long ruler held by her professor (who is moving relative to her) is the same as that of her meterstick (when oriented parallel to his ruler).
(a) What is their relative speed (assuming they are moving in a direction parallel to their respective sticks)?
(b) If the professor takes 5.00 min to write an email according to his watch, how long did it take him to write it according to the student?