Sometimes I wonder if we can send some of our students to the International Space Station (ISS) for a homestay. With gravity and friction out of the way, it is pretty obvious that all a mass wants to do, is to be stick to its current motion. No need for any teaching, every student understands immediately maintaining motion requires no force.
Better still, throw the student out of the ISS. With nothing to push/pull against, the student immediately learns that his current motion cannot be changed without an unbalanced force.
This reminds me of the scene in the movie “Mission to Mars”, where the crew were forced to abandon ship and take refuge in the REMO (“Resupply Module”) orbiting Mars. The plan was for Woody to launch himself at the module and attach a tether to it.
It was Woody’s inertia that killed him. Unable to conjure any force to act on himself, he was doomed to carry on moving at his current velocity. (In the movie it was suggested that eventually Woody was accelerated by Mars’ gravity and burnt up as he sped through the Martian atmosphere.)