What is the applications of echo

When a sound wave is produced in air, some of it is absorbed after hitting with a reflector while some of the sound wave is reflected back to the listener. This reflected sound is called echo.

Applications of Echo:

Since bats cannot see from their eyes, so they use the technique of echolocation to locate their ways. Bats can understand from the reflected sound if there is any object before it. It hunts its prey by using this technique.This technique is also used to find the depth of sea or distance of submarinesIt also helps to estimate the distance or hills and mountains.This technique is also very helpful in the medical field as well. Doctors used this phenomenon in cardiography, sonogram and many other medical diagnosis.

If football was tossed in air without gravity or friction the ball would go into space