Now here comes the tricky part. Once you give the car a push, it is in motion. It wants to stay in motion. But we all know that the toy car will eventually slow down and stop. Because a force called friction is slowing it down.
Friction happens when things rub against each other, and it slows down things in motion.
The toy car's tires rub against the floor, causing the friction that slows it down. Even the air the car moves through creates friction. The best place to test inertia is outer space. In outer space there is no air, or anything else to create friction. So moving objects will keep moving forever, and objects that aren't moving will stand still forever.