Relativistic Mass is: $$ m_r = \frac{m}{\sqrt{1 - v^2/c^2}} $$
So Einstein says that the faster an object moves, the more mass it gains (relativistic mass). So suppose you have a spherical ball with a radius of 10 meters and a resting mass of 100kg that is spinning on an axis. In fact, this ball is spinning so fast that any point on the equator is traveling at $0.9c$ around the axis. What is the relativistic mass of the ball when it is spinning at this speed?
I thunk up an integral that might describe it but I don't know. (based on a cartesian plane.) The equation for the velocity at any given point is (Revolutions/s*2piRadius)=Velocity. Radius = sqroot(x^2+y^2+z^2). RadiusRevolutions/s*2pi=v. Triple Integral replacing that equation for v of the relative mass equation?
