# units of force | # rotations | time (s) | Frequency (Hz)
==========================================================
6                | 20          | 25.77    | .7761
10               | 20          | 20.90    | .9569
14               | 20          | 18.62    | 1.074
18               | 20          | 16.71    | 1.197
22               | 20          | 13.85    | 1.444
26               | 20          | 12.58    | 1.590
30               | 20          | 11.65    | 1.717

2x mass ball:
12               | 20          | 25.10    | .7968