noun
propulsive power; driving force
Refers to the force that pushes something forward, both literally (physics, engineering) and figuratively (motivation, momentum behind a project or movement).
ロケットの推進力は燃料の燃焼によって生まれる。
A rocket's propulsive power is generated by the combustion of fuel.
彼の熱
His enthusiasm became the driving force behind the project.