# Speed of sound with a ball on the end of a string

1. Jan 1, 2012

### whoeli

When I was younger I had a ball on a string. For what it's worth, the ball was quite a dense rubber, and about two inches in diameter and spherical, so I think it weighed about two-and-a-bit ounces, maybe two-and-a-half. The string was about a metre long, and it was very stretchy...

Once I took it outside and swung it over my head like a bullroarer (like this guy: ). The string stretched out, but stayed intact, so as the ball swung around me it gave a "circle" of about 11 metres' diameter... and since I remember I managed to get about six revolutions per second, the ball was travelling about 210 metres per second.

Aside from a bang (?), what would have happened had I managed to get the ball to move faster than sound? (That's what I was trying to do but I just... couldn't... do it.)

Last edited by a moderator: Sep 25, 2014