LAWS OF MOTION
Each
and every object in the universe interacts with every other object. The cool
breeze interacts with the tree. The tree interacts with the Earth. In fact, all
species interact with nature. But, what is the difference between a human’s
interaction with nature and that of an animal’s. Human’s interaction has one
extra quality. We not only interact with nature but also try to understand and
explain natural phenomena scientifically.
In
the history of mankind, the most curiosity driven scientific question asked was
about motion of objects-‘How things move?’ and ‘Why things move?’ Surprisingly,
these simple questions have paved the way for development from early
civilization to the modern technological era of the 21st century.
Objects
move because something pushes or pulls them. For example, if a book is at rest,
it will not move unless a force is applied on it. In other words, to move an
object a force must be applied on it. About 2500 years ago, the famous
philosopher, Aristotle, said that ‘Force
causes motion’. This statement is based on common sense. But any scientific
answer cannot be based on common sense. It must be endorsed with quantitative
experimental proof.
In
the 15th century, Galileo challenged Aristotle’s idea by doing a series of
experiments. He said force is not required to maintain motion.
Galileo
demonstrated his own idea using the following simple experiment. When a ball
rolls from the top of an inclined plane to its bottom, after reaching the
ground it moves some distance and continues to move on to another inclined
plane of same angle of inclination as shown in the Figure 3.1(a). By increasing
the smoothness of both the inclined planes, the ball reach almost the same
height(h) from where it was released (L1) in the second plane (L2) (Figure
3.1(b)). The motion of the ball is then observed by varying the angle of
inclination of the second plane keeping the same smoothness. If the angle of
inclination is reduced, the ball travels longer distance in the second plane to
reach the same height (Figure3.1 (c)). When the angle of inclination is made
zero, the ball moves forever in the horizontal direction (Figure 3.1(d)). If
the Aristotelian idea were true, the ball would not have moved in the second
plane even if its smoothness is made maximum since no
From this simple experiment, Galileo
proved that force is not required to maintain motion. An object can be in
motion even without a force acting on it
In
essence, Aristotle coupled the motion with force while Galileo decoupled the
motion and force.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.