Law of inertia, also known as Newton’s first law of motion states that An object will continue to be in the state of rest or in a state of motion unless an external force acts on it. We have read about the Aristotle fallacy, as per which an external force is always required to keep a body in motion.
Explanation:
Galileo’s Free Fall Experiment
The most accepted theory of motion in Western philosophy, prior to the Renaissance, was the Aristotelian theory which stated that “In the absence of external power, all objects would come to rest that moving objects only continue to move so long as there is a power inducing them to do so. ” Despite its general acceptance, the Aristotelian theory was discredited by several notable philosophers. Later, Galileo refined the theory of inertia.
How did Galileo Explain Inertia?
Galileo hypothesized that a falling object gains an equal amount of velocity in equal intervals of time. This also means that the speed increases at a constant rate as it falls. But, there was a problem in testing this hypothesis: it was impossible for Galileo to observe the object’s free-falling motion and at the time, technology was unable to record such high speeds. As a result, Galileo attempted to decelerate its motion by replacing the falling object with a ball rolling down an inclined plane. Since free-falling is basically equivalent to a completely vertical ramp, he assumed that a ball rolling down a ramp would speed up in the exact same way as a falling ball would.
Using a water clock, Galileo measured the time it took for the rolling ball to reach a known distance down the inclined plane. After several trials, it was observed that the time it took for the ball to roll the entire length of the ramp was equal to double the amount of time it took for the same ball to only roll a quarter of the distance. In short, if you were to double the amount of distance the ball traveled, it would travel four times as far. Through this experiment, Galileo concluded that
If an object is released from rest and gains speed at a steady rate (as it would in free-fall or when rolling down an inclined plane), then the total distance, s, traveled by the object is proportional to the time squared needed for that travel.
