noun
Physical sense: the tendency of a moving object to keep moving, or a stationary object to stay still. Also used figuratively for the momentum of a situation or activity.
車は惰力でしばらく進んだ。
The car coasted for a while on its momentum.
会議は惰力で続いているだけだ。
The meeting is just continuing out of inertia.
noun
The tendency to continue doing something simply because one has always done it, without conscious thought.
惰力で毎日同じ道を通っている。
Out of force of habit, I take the same route every day.