The Various Principles of Dynamics

Abstract

Dynamics is the science of accelerating or retarding forces and the diverse motions which they produce. This science is entirely due to modern investigators and it is Galileo who developed its basic principles. Before him, only forces applied to bodies in a state of equilibrium were considered and although the cause of the acceleration of heavy bodies and the curvilinear motion of projectiles could not be attributed to anything but the constant action of gravity, no one had been able to determine the laws of these common everyday motions with such a simple cause. Galileo was the first to make this important step and by his discovery began a new and vast development for the advancement of mechanics. This discovery is formulated and developed in the work entitled Discorsi e dimostrazioni matematiche intorno a due nuove scienze ¹ which was published for the first time at Leyden in 1638. It did not bring him as much fame during his lifetime as the discoveries made in the skies, but this discovery constitutes the most solid and real part of the glory of this man.