The coordinates of two spacetime events are given by (ct1, x1) = (2,5) and (ct2, 22) = (3, 3) in an inertial reference frame k. (a) calculate the squared spacetime interval between these events. is their spacetime separation spacelike or timelike? (b) transform the co-ordinates of this pair of events to a new reference frame, k' moving relative to the one used in (a) with a constant speed u = -2 x 108m/s in the ection. explicitly show that the squared spacetime interval between the events is the same in the new reference frame. (c) compare the time ordering of events in the two reference frames - you should find that the ordering has changed. in general such a change of ordering would lead to causal paradoxes, for example: the girl calls her dog, the dog obeys; versus, the dog obeys, the girl calls her dog. explain (with the aid of a spacetime diagram) why this is not a problem in the case of the events analysed in this question.