Newton’s Laws of Gravity and Accelerated Motion
Newton’s laws don’t just apply to inertial frames of reference, the Galilean transform just happens not to work between accelerating frames of reference.
Newton's Laws of Motion
Newton associated forces to acceleration, rather than a kind of velocity. His first and second laws of motion stated that no matter how fast an object is moving, if the object is not accelerating, then there are no forces acting on it and that the acceleration is proportional to the force in the direction of that force.​
https://www.slideshare.net/amandayoung313/newtons-second-law-8084901
Newton's Gravitation
There was another fascination of Newton's though. A mysterious force at a distance by the name of gravity. Gravitation is the attraction of objects, by means of a force, directed towards each other. The strength of this force is proportional to the product of the two objects’ masses and inversely proportional to the square of the distance between the two objects’ centers of mass. He believed that this wasn’t just the force that pulled objects to the ground, but also kept celestial bodies like our moon in orbit around larger masses.