Rope Around The Earth

Imagine there s a rope around the equator of an earth sized sphere making it around 25 000 miles long.

Rope around the earth.

How much longer must it be for it to be one foot off the ground all the way around the equator. If you put 1 metre high sticks right around the equator and lay the rope on. 2pi or approximately 6 28 feet for both the basketball and the earth. 40 000 divided by 2 is 20 000.

From the diagram it s pretty clear it s one foot. The idea is to imagine the earth is a cube or just a square really and ask yourself if you added say 8 feet to the rope how far would that raise it above the square earth. Imagine a rope tied around the earth s equator like a ring on a person s finger. Divide again by pi to get the earth s radius 6 370km.

As a circle of radius r has a circumference of 2 π r regardless of the value of c. Student answer form blackline master rope around the world you have a piece of rope that just fits around the earth. From there it s not hard to believe that adding 3 feet to a rope around the actual earth would raise it almost 6 inches. Rope around the earth puzzle imagine a rope that fits snugly all the way around the earth like a ring on a person s finger.

A corollary is that to raise the original string 16 cm 6 3 in off the ground all the way around the equator only about 1 metre 3 ft 3 in needs to be added. Now imagine the rope is made just one meter longer and lifted uniformly off the surface until it is once again taught. This below is one answer i saw. Now imagine lifting off this very long rope don t ask me how cutting it somewhere so as to stitch into it exactly one meter of extra rope.