Final answer:
Secretariat's plausible unit speed for the Belmont Stakes is 36 mph, calculated by correcting the track length to 1.5 miles, not the erroneous 17 miles given in the question. The corrected speed calculation uses the formula: speed = distance / time.
Step-by-step explanation:
The student asked about the unit speed of Secretariat during the Belmont Stakes when he completed the race in 2 minutes and 30 seconds on a track known as "Big Sandy", which is 17 miles long. To find Secretariat’s unit speed, we use the formula for speed: speed = distance / time. We know the distance (17 miles) and the time (2 minutes and 30 seconds, which we need to convert into hours as we're looking for the speed in mph). 2 minutes and 30 seconds is equivalent to 2.5 minutes, which is 2.5/60 hours (or 1/24 hours).
Now we can calculate: speed = 17 miles / (1/24 hours) = 17 miles * 24/1 hours = 408 mph. However, this result is not reasonable for a horse race as horses do not run that fast. There is likely an error in the size of the race track provided in the question, since the Belmont Stakes is actually run over a distance of 1.5 miles, and not 17 miles. Assuming a 1.5-mile distance, the calculation would be: speed = 1.5 miles / (1/24 hours) = 1.5 miles * 24/1 hours = 36 mph, which is a plausible speed for Secretariat during the Belmont Stakes.