OR The law of inertia Inertia is the tendency of an object to resist motion. This directly relates to mass, greater mass = greater inertia.
One of the most common places people feel the first law is in a fast moving vehicle such as a car or a bus that comes to a stop .
The crash dummy is not wearing a seat belt and is moving along with the car. Both the car and the dummy are moving at, say, 60 mph.
When the car hits the cement road divider it is stopped (an outside force stops it from moving). The crash dummy, however is not so lucky. Since he is not wearing a seat belt, and is not connected to the car, he will continue to move at 60 mph. This means he will go flying out through the front windshield
The dummy will fly through the air until he hits the ground. This is because the earth's gravity stopped him from moving any further. If this collision had happened in zero-g, in a vacuum, the dummy would theoretically keep on hurtling away from the car at 60 mph.
According to Newton's first law, an object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
And really, it’s the force of friction that brings the rider to a halt .