I remember at some point watching the Mythbusters episode where they “bust” that running in the rain will get you less wet than walking will. From that moment on, I’ve always patiently walked under the nearest room during flash rain storms rather than sprint with everyone else. Turns out, they’re tests using artificial rain gave a false negative, and under real rain situations, running does get you less wet than walking does.
MinutePhysics uses some parallelepipeds (remember those from calculus?) to mathematically show why running is a better mode of travel than is walking in the rain. (Thankfully) They don’t formally use any calculus, but the demonstrations still pretty convincing.