Aristotelian and Galilean Concept of Motion

Nature of Motion

The study of how objects move and the forces that affect their motion.

Aristotelian Concepts on Motion

Aristotle believed that force exists within an object and determines its behavior. Motion depends on the nature of the substance moving and is classified into natural motion and violent motion.

Natural Motion

According to Aristotle, an object moves and eventually returns to its natural state depending on its composition.

Violent Motion

According to Aristotle, an object moves when an external force such as pushing or pulling is applied.

Aristotle’s View of Force

Force is the controlling factor and the reason why motion occurs.

Aristotle’s View of Heavenly Motion

The laws governing the motion of the heavens were different from the laws governing motion on Earth.

Galilean Concepts on Motion

Galileo believed that motion is a natural state that continues until altered. Force is an interference to motion rather than its cause.

Galileo’s Principle of Motion

Motion continues unless it is interfered with.

Acceleration Due to Gravity

Galileo discovered that gravity causes acceleration at a rate of 9.8 m/s².

Vertical Motion

The movement of objects upward or downward due to forces such as gravity.

Aristotle’s Vertical Motion

Aristotle believed that the behavior of objects depends on their composition. Heavy objects move downward due to gravity, while light objects move upward due to levity.

Gravity and Levity

Aristotle’s concepts referring to heaviness and lightness as factors that determine an object’s natural motion.

Galileo’s Vertical Motion

Galileo established that free-fall acceleration is uniform and constant for all objects regardless of size and weight, with an acceleration of 9.8 m/s².

Projectile Motion

The motion of an object moving through the air that combines horizontal and vertical movement.

Aristotle’s Projectile Motion

Aristotle believed that an object moves horizontally due to an “impetus” until the force is used up, causing it to fall to the ground.

Impetus

A force believed by Aristotle to keep a moving object traveling in the same direction until it is exhausted.

Galileo’s Projectile Motion

Galileo explained that projectile motion is a combination of constant horizontal velocity and vertical acceleration of 9.8 m/s².

Acceleration in a Vacuum

In a vacuum, where there is no air resistance, objects fall with uniform acceleration because no interference affects their motion except gravity.

Air Resistance

A type of friction caused by air that opposes motion and slows down moving objects.

Galileo’s Assertion of Frictionless Motion

If friction were absent, a rolling ball would continue moving with constant velocity unless a push or pull changes its state.

Newton’s Law of Inertia

A body remains at rest or moves in a straight line with constant velocity if no external forces act on it.

Difference Between Galileo and Newton’s Ideas

Galileo used the terms “push or pull” to explain changes in motion, while Newton used the term “force.”