What is the Law of Inertia as noted in the nonfiction book, The New Way Things Work?

The Law of Inertia states that an object in motion tends to remain in motion. More specifically, an object is resistant to changing speed or direction. That means to set an unmoving object into motion will require a force to overcome inertia, and to stop that same object once it is moving will require another force to counter inertia. Inertia also creates centrifugal force. Machines are built out of fixed and moving parts and their movement requires forces to overcome inertia.