Can a Horse Fly?
Why am I bothering with such a silly question? Because Egyptians are tying themselves in knots arguing about whether this actually happened 1400 years ago. Not to pick on the Egyptians, (nice people,) everybody else believed in flying horses at some point. in any case, the answer is “No! Horses cannot fly!” And here is why (*):
1. Typical weight of a horse: ~ 300 Kilogram. (**)
2. The weight of a horse + rider: W(h+r) = ~ 370 Kg.
3. The force required to lift the horse & rider: ~ 370 X 9.81 = 3,630 Newton. [9.81 m/s.s is g, the acceleration due to gravity.]
4. Suppose the horse and the rider rose up 10 kilometers. Then they acquired a potential energy: E(p) = W(h+r) X 10,000 m = ~ 36,300,000 Joules.
5. To get there, the horse needs to expend an equal amount of kinetic energy E(k) = E(p) = ~ 36,300,000 Joules.
6. In order to do that in, say, 10 minutes, the horse needs to have the power P = E(k) / (10 X 60) = ~ 60,500 Watts = ~ 81 horsepower
This means that the horse needs to have the power of 81 horses to fly. There is no such horse. (In scientific terms, the ability to fly is determined by the power-to-weight ratio. In creatures meant to fly, that ratio is quite high. In earth-bound creatures, like us and horses, it is far too low.)
This type of simple analysis (based on first principles,) is called “back-of-the envelope” calculation. It is aimed at quickly finding a rough estimate. I encourage professors of science and engineering to train their students in this type of analysis.
Here is another back-of-the-envelope calculation to show that horses can’t fly::
– Energy needed for the 10-Km flight is 36,300,000 Joules = 8,676 Kilocalories
– Number of calories in a Kilogram of hay: 600
– Number of kilograms of hay necessary for 1-way journey = 8,676 / 0.6 = 18,333 Kg.
– Capacity of the horse’s digestive system: ~ 20 gallons, or 12.5 Kg of hay max.
This means that the horse can never have enough energy to make the trip on one feeding. (That is why horses continuously feed and poo all day.)
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*) Some knowledge of elementary physics is required to follow.
**) All numbers are rounded. The sign ~ means approximately.
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مؤسسة ندى لحماية الفتيات
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