Force and Laws of Motion

In the previous chapter, we described the motion of an object along a straight line in terms of its position, velocity, and acceleration.
We saw that such a motion can be uniform or non-uniform. We have not yet discovered what causes the motion. Why does the speed
of an object change with time? Do all motions require a cause? If so, what is the nature of this cause? In this chapter, we shall make an
attempt to quench all such curiosities. For many centuries, the problem of motion and its causes had puzzled scientists and philosophers. A ball on the ground, when given a small hit, does not move forever. Such observations suggest that rest is the “natural
state” of an object. This remained the belief until Galileo Galilei and Isaac Newton developed an entirely different approach to
understand motion.