>>> import pandas as pd
>>> import pint

>>> df = pd.DataFrame({
...     "torque": pd.Series([1, 2, 2, 3], dtype="pint[lbf ft]"),
...     "angular_velocity": pd.Series([1, 2, 2, 3], dtype="pint[rpm]"),
... })
>>> df['power'] = df['torque'] * df['angular_velocity']
>>> df.dtypes
torque                                       pint[foot * force_pound]
angular_velocity                         pint[revolutions_per_minute]
power               pint[foot * force_pound * revolutions_per_minute]
dtype: object