Newton’s first law
Nothing moves without a little push first. That’s essentially Isaac Newton’s first law of motion. If an object is moving at a constant speed (even if the speed is zero, and the object is stationary), it will stay that way unless a force, like the friction between a wheel and the ground, affects it.
This concept is also called inertia. Newton’s first law explains why once a rocket is launched into the vacuum of space, without the resistance of air or other forces, it will keep traveling in a straight line at a constant speed indefinitely.
