MOTION

• Aristotle held that the Universe was divided into two regions, the terrestrial region and the celestial region
• The celestial region is made up of the Sun, Moon, planets, stars, comets, etc.
• Aristotle also divided motion into two main classes which are natural motion and violent motion.
• Galileo Galilei believed that a projectile motion is a combination of uniform motion in the horizontal direction and uniformly accelerated motion in the vertical direction.
• Motion


  is the action of changing location or position.
• Vertical motion (aristotle)


  Vertical motion is referred to as natural motion. In a natural motion, the object will move and will return to its natural state based on the object's material or composition - earth, water, air, and fire.
• Horizontal motion (aristotle)


  An object moving in a violent motion requires push or pull to maintain horizontal motion. Motion continues only so long as there is an applied force to an object. When the force is removed, motion stops.
• Projectile Motion (aristotle)


  Aristotle believed that the projectile motion of an object is parallel to the ground until it is the object's time to fall back into the ground. An impetus will be kept by the object until such time that the initial force is forgotten, and the object returns to its natural state to stop moving and fall to the ground.
• According to aristotle, heavy objects fall faster than light ones
• Vertical motion (galileo galilei)

  In the absence of a resistance, objects would fall not depending on their weight, but in the time of fall. Also, if the object encountered a resistive force from a fluid equal or greater than its weight, it will slow down and reaches a uniform motion until it reaches the bottom and stops.
• Horizontal Motion (galileo galilei)


  An object in motion, if unimpeded, will continue to be in motion, and an external force is not necessary to maintain the motion. If the Earth’s surface is very flat and extended infinitely, objects that are pushed will not be impeded. Thus, the objects will continue to move. This kind of motion, however, is not evident in nature.
• Projectile Motion (galileo galilei)

  Galileo performed experiments on uniformly accelerated motion using an inclined plane, and used the same apparatus to study projectile motion.
• By varying the ball's horizontal velocity and vertical drop, Galileo was able to determine that the path of a projectile is parabolic.
• Uniformly Accelerated Motion


  In the absence of air resistance, all objects fall at the same constant acceleration no matter how light or heavy it is.
• Galileo was fascinated by the behavior of falling objects. He knew that falling objects increase their speed as they go down. This change in speed is acceleration.
• Freely falling bodies undergo constant acceleration in which it is referred to as free fall. The free fall acceleration represent a symbol g which means gravity.
• At the surface of the earth, gravity (g) is approximately 9.8 m/s2.
• Gravity leads the object to accelerate in a constant rate.
• These observations lead Galileo to conclude that regardless of the mass of objects and air resistance, falling objects would always have uniform acceleration
• Galileo’s observation also suggested that in vacuum, all objects would fall with the same acceleration regardless of the weights.
• Distance is the total length or ground covered by an object
• Displacement is the change in the position of an object or the shortest distance between the initial and the final position of an object.
• Speed 


  how fast the object is moving and can be calculated by dividing the total distance by the total time spent to cover that distance.
• Velocity


  how fast and where the object is moving and can be calculated by dividing the displacement of an object to the time spent.
• Acceleration


  change in the velocity of an object per unit time. An object accelerates when there is:

  • Changing speed • Changing direction • Changing speed and direction
• Mass


  is the amount of matter or substance that makes up an object. It is measured in units called kilogram.
• An object with a greater mass has a greater inertia and an object with a lesser mass will also have a lesser inertia.
• Inertia of rest


  an object will stay in place unless something or somebody moves it.
• Inertia of motion


  an object will continue at the same speed until a force acts on it.
• Inertia of Direction


  an object will stay moving in the same direction unless a force acts on it.
• Force


  A force causes an object to move, to stop or remain at rest.
• Newton (N)


  unit of force
• Friction


  a force that opposes motion between any surfaces that are touching. Occurs because no surface is perfectly smooth.
• Balanced Force


  A balanced force is a force in which the net force is equal to zero.
• Unbalanced Force


  An unbalanced force is a force in which the net force is greater than zero.
• 3 rd Law: Law of Action/Reaction
• 2 nd Law: Law of Acceleration