A potter's wheel is rotating around a vertical axis through its center at a frequency of 1.8 rev/s. The wheel can be considered a uniform disk of mass 4.9 kilogram and diameter 0.36 meter. The potter then throws a 3.1 kilogram chunk of clay, approximately shaped as a flat disk of radius 15 centimeter, onto the center of the rotating wheel.
Find the frequency of the wheel after clay sticks to it?