For this problem, assume that any two frames have the same origin. Consider two events with coordinates (t_1, x_1) and (t_2, x_2) in an inertial frame of reference S. The coordinates of these two events in an inertial frame S' moving to the right with speed u relative to frame S are (t_1', x_1') and (t_2', x_2'). If we assume that the y and z coordinates are constant in the two frames, then x_2' - x_1' the space interval, more commonly known as distance, between the events as measured in frame S', and x_2 - x_1 is the space interval in the frame S. These two intervals are more commonly written Delta x' and Delta x, respectively. Similarly, t_2' - t_1' is called the time interval between the events in frame S', and t_2 - t_1 is called the time interval in frame S. These two intervals are more commonly written Delta t' and Delta t, respectively. Part B A pair of events are observed to have coordinates (0 s, 0 m) and (50.0 s, 9.00 times 10^9 m) in a frame S. What is the proper time interval Delta t_proper between the two events? Express your answer in seconds to three significant digits. Delta t_proper = s