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It is that case that $$\sqrt5\frac{\text{mile}}{\text{hour}} = \frac{\text{m}}{\text{s}}$$ almost exactly, so of course also $$5\frac{\text{mile}}{\text{hour}} = \sqrt5\frac{\text{m}}{\text{s}}.$$ I would find this more delightful if it hadn't just caused me so much confusion. I couldn't figure out whether I was supposed to multiply or divide because the number was the same both ways around. Still it might make a useful mnemonic, if I could remember which way around it was.
