Dear r_dela...:

On Thursday, June 20, 2013 7:28:24 PM UTC-7, wrote:
How fast would the earth have to spin, so that stuff
started flying off?

Others have given you an answer based on the Earth being a solid body with its current shape.

The Earth is like a creme filled chocolate, and if you even tried to double its speed, it would lobe up, and spin off another Moon. Even a 50% increase would be pretty disastrous.

David A. Smith