Example:
15 W = 0.020115 horsepower (550 ft·lbf/s)
1 W = 0.001341 horsepower (550 ft·lbf/s) | 1 horsepower (550 ft·lbf/s) = 745.699872 W
Conversion Steps:
15 × (1 / 745.699871582) = 0.020115331