The Aristotelian and Galilean Conceptions of Motion
Motion is the action of changing location or position. Life is motion. From the coordination of the
muscles of our body which enables us to walk, run and dance to the pumping of our hearts to
deliver
blood to the different parts of the body are motion.
The Aristotelian and Galilean Conceptions of Vertical, Horizontal, and Projectile Motions
Motion is the action of changing location or position.
Horizontal and vertical motion and projectile motions can be derived from the quantification
of the "RATE OF FALL"
or "ACCELERATION"
Aristotelian Concept of Motion
According to Aristotle, motion is divided into two
main classes:
● NATURAL MOTION and
● VIOLENT MOTION.
1. In a natural motion, objects move and return to its natural state based on its material or
composition. While Vertical Motion is natural motion.
● When a thing thrown upward falls down, its element was earth.
● Smoke goes up in the air because it is on its natural place.
2. An object moving in a violent motion requires push or pull to maintain horizontal
motion.
3. Projectile motion of an object is parallel to the ground until it is the object's time to fall
back into the ground. It is both natural and violent motion.
Galilean Concept of Motion
Galileo Galilei -an Italian physicist considered as the "Father of Modern Physics".
In the absence of resistance, objects would not fall depending on their weight, but in the time of
fall.
An object in horizontal motion, if unimpeded, will continue to be in motion, and an external force
is not necessary to maintain that
motion.
Galileo dropped two different weights of cannon balls in the
Leaning Tower of Pisa.
a. In Galileo Galilei’s Uniform Acceleration, both the cannon balls with different weight will
hit the ground in the same time regardless of their heigh, weight, size.
b. On the other hand, in Isaac Newtons Law of motion, if there is resistance the heaviest
will fall first.
Galileo used the inclined ramp to measure the acceleration of
● As the ball falls its speed increases into 2m/s.
● A ball rolling down an inclined plane increases its speed by the same value after every
second. The ball increases speed by 2 m/s every second.
Speed is the distance travelled by an object divided by the time taken to travel the distance.
Galileo's Concept of Inertia
The first concepts of laws of motion was developed by Galileo after his experiments.
● the concept of velocity
● the idea of force that causes motion
● the natural state of an object is rest or uniformed motion
● objects resists motion, inertia
Isaac Newton & The First Law of Motion
Isaac Newton expanded Galileo's work and came up with his Three Laws of Motion
First Law of Motion (Inertia) - object at rest stays at rest and object in motion stays in motion
with the same speed and in the same direction unless acted upon by an unbalanced force.
Mass and Inertia
Mass is proportional to its inertia.
● For example, a motor vs. truck. The truck has more inertia since it is heavy and harder to
stop when it is running downhill.
● If the object is heavy then it has more inertia. On the other hand, if the object is not
heavy then it has less inertia.
Types of Inertia
1. Inertia of Rest -an object will stay in place unless something moves it.
2. Inertia of Motion -an object will continue at the same speed until a force acts on it
3. Inertia of Direction -an object will stay moving in the same direction unless a force acts
on it
Force is defined as a push or pull. It is measured in Newtons (N).
1 newton = 1 kg x 1 m/s/s
1 newton = 1 kg.m/s2
Friction is a force that opposes motion between any surfaces that are touching.
● Rough surfaces have more friction than smooth surfaces.
● Heavier objects have more friction
● Friction produces heat.
Balanced and Unbalanced Force
Balanced force occurs when the NET FORCE is
equals to zero.
Net force is the total combination of forces acting on
an object.
Unbalanced force occurs when the net force is greater than zero
Galileo's Inertia and Newton's
First Law of Motion Galileo described inertia as the resistance of an object to any change in its
velocity, while Newton explained the relationship between the motion of the object and the
forces that are acting upon it.
