In the chapters Straight line motion and Motion in 2 and 3 dimensions we were studying Kinematics – the study of motion of objects without considering the causes of this motion. Now we will start studying Dynamics - a branch of mechanics that deals with forces and their relations to patterns of motion.
The fundamental laws of Dynamics were formulated by Isaac Newton (1642 – 1727). He created a system of mechanics that is considered as one of the greatest intellectual achievements of all time.
The three laws of dynamics formulated by Newton must be discussed nearly simultaneously, because it is difficult to imagine a situation where only one of them is sufficient to explain the existing situation or the phenomena observed by us. We introduce the Newton laws in “reverse order” as such sequence of explanations may be easer to understand.
It is worth mentioning that what is sometimes called Newtonian Mechanics or Classical Mechanics cannot be applied to situations where the speed of a moving object is approaching the speed of light – approximately THREE HUNDRED THOUSAND kilometers per second, or to write it in scientific notation and in SI units - 3.0x108 m/s.
This is an extremely unusual speed for everyday life situations, but later on we will also come across problems involving objects moving at such speeds.