Weight dependent on planet size and rotation speed?

[NHsolarguy]

Hi,
I recently read a sci-fi story where they implied that the planet was much larger than Earth, but because that planet was rotating much faster than Earth, a person's weight on this planet was similar to what it was on Earth. I always thought it was strictly the masses that controlled this... However, intuitively, if a body was rotating fast enough, I would think it would tend to fling away objects from the surface... So it certainly seems possible that rotation could affect weight. Does anyone have an equation handy for this?
thanks!

 

[russ_watters]

Surface gravity depends on mass, density, and rotation rate. The equation for the rotation's effect is the centripetal force equation: http://en.wikipedia.org/wiki/Centripetal_force