Cheetahs are big cats that live in Africa, Asia, India and the Middle East. They can run super-fast to catch their prey when they are hunting for food. But running at top-speed is very tiring, so cheetahs only do it for short periods of time.
My 6-year-old wondered, what if a cheetah could run at its top-speed without getting tired…? How long would it take the cat to run all the way around the world?
Let’s do the maths and find out!
In order to work out this sum, we need to know two things: the speed at which a cheetah can run and the circumference of the Earth (that is, the distance around the middle).
- A cheetah’s fastest run is about 110 kilometres per hour. That’s about 68 miles per hour – roughly the same speed as cars driving along a motorway!
- The circumference of the Earth at the equator (the imaginary line around the middle of the planet) is 40,075 kilometres, or 24,901 miles.
If we assume our cheetah can run the whole distance at top-speed, how long will it take him/her to run around the equator? To work it out, I divided the Earth’s circumference by the speed at which the cheetah can run:
40,075 / 110 = 364 hours
…and since there are 24 hours in a complete Earth day, I divided the number of hours by 24 to find out the number of days it would take:
364 / 24 = 15 days
Wow! It would take our cheetah 15 days to run around the world!
Can you work out how long it would take other animals to make the round-the-world journey? What about a garden snail (top-speed 0.05 kilometres per hour)? Or a chinchilla (top-speed 24 kilometres per hour)? Or a person (top-speed 44 kilometres per hour)? Try to work out the answer for your favourite animal!