Life is A Test 2: Test Harder (Quite A Bit Harder)

by Brony_of_Brody

The Answer 36

For the fastest time, there needs to be no wind at all.

Let's imagine a case where the wind blows totally in Rainbow Dash's direction for the trip outward, and against her for the return. Instinctively, the first thought is that it shouldn't matter, because in terms of speed, what the wind giveth in one direction, it taketh away in the other. If the wind speed is W, then the speed there is Rainbow's speed + W, and the speed back is RD's speed - W.

But it's TIME that's important here, not speed. Rainbow will naturally, spend a longer time flying slower than she would flying faster.

It's easy enough to prove without any tricky maths. Let's imagine that the wind speed was equal to that of Rainbow's speed. She could make the outward journey in half the time, but the return trip? Her return speed is equal to that of the wind's speed: she wouldn't actually be able to even get off the ground, because they cancel each other out!

Okay, that's a bit extreme, but you see the point. You may gain an hour by raising speed by a fixed amount, but you may lose a lifetime by decreasing speed by the same fixed amount.

What about crosswinds though? Well, they depend on how much of the wind is going against Rainbow, whether it's buffering her at a 90 degree angle or if there's enough wind blowing against her. But even then, in order to not get blown off course, Rainbow would have to exert some energy flying directly into a perpendicular wind, so naturally, some of the velocity would be spent fighting the wind, rather than travelling from A to B. So even then it will still take Rainbow longer.

That must be why Spitfire chose this demerit: there's no way to cheat that won't slow Rainbow down in the long run. It's all muscle-flying.

Comments

[farsan]

An alternative answer: The wind must blow as upwards as possible, with as less horizontal direction as possible.

[Brony_of_Brody]

9735807

What about crosswinds though? Well, they depend on how much of the wind is going against Rainbow, whether it's buffering her at a 90 degree angle or if there's enough wind blowing against her. But even then, in order to not get blown off course, Rainbow would have to exert some energy flying directly into a perpendicular wind, so naturally, some of the velocity would be spent fighting the wind, rather than travelling from A to B. So even then it will still take Rainbow longer.

Read this again.