You see a system consisting of a mass oscillating on the ena or a sprmg pass period of the system is t. your strange friend, who is moving with the mass-spring system, also measures its period and finds a period that is a) d) e) b) either a or b depending on whether the system was there is not sufficient information to answer the question. less than t c) greater than t equal to t approaching or receding from the first observer. a atondard canadian foothall field is 100 m long and 60