In a high-school 100 m sprint, the elapsed time attributed to the winner is the (ending time) - (starting time) or $\Delta t = t_{end} - t_{start}$. However, due to human reaction time, there is an inherent uncertainty in both of these times. Assume that the uncertainty for each reading is the same with $\omega_t = (0.07 + \psi/900)$ s. Find the uncertainty in the actual elapsed time if the recorded time was 10.83 s.
