Example:
15 mW = 0.00002 horsepower (550 ft·lbf/s)
1 mW = 0.000001 horsepower (550 ft·lbf/s) | 1 horsepower (550 ft·lbf/s) = 745699.871582 mW
Conversion Steps:
15 × (0.001 / 745.699871582) = 0.000020115