Newton-meters
A newton-meter (Nm) is primarily used to quantify torque which is the rotational force applied to an object. It is the force of one newton applied perpendicularly to a lever arm one meter long.
Btu
The British Thermal Unit (Btu) is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is primarily used in the United States to describe the energy content of fuels and the power of heating and cooling systems.