A marathon runner completes a 42.188-km course in 2 h, 21 min, and 23 s. there is an uncertainty of 30 m in the distance traveled and an uncertainty of 1 s in the elapsed time. (a) Compute the percent uncertainty in the distance. (b) Compute the percent uncertainty in the elapsed time. (c) What is the average speed in meters per second? (d) What is the uncertainty in the average speed?