II. ACTIVITY 2. FILL IN THE BLANKS: Choose from the box below word/s that will complete the article.

ITS ALL ABOUT MOTION

Two important historical figures in physics, Aristotle and Galiloe shed light to the understanding of motion. Though the two proposed opposing views on motion but still they helped science progress.

According to1. __________________, motion is classified into two; natural motion and violent motion. An object will move and will eventually return to its natural state depending on the composition that the object is made of. This referred as the 2. __________________ of an object. An object will move if an external force such as pushing or pulling is applied to it. This is referred as the 3. ____________________________ of an object. The motion of an object is 4. _______________________________ until it reaches the object's time to fall back into the ground. This is referred as the projectile motion of an object.

However, Galileo have a different perspective with motion. Acoording to him, an object in 5. _________________ will travel a distance that is 6. ______________________ to the time it will take to travel; a uniformly accelerating object will travel at a speed and proportional to some factor of time; and an object in motion, if unimpeded, will 7. ______________ to be in motion; an external force is not necessary to maintain the motion. He also believes believed that a projectile is a combination of uniform motion in the 8. __________________________ and uniformly accelerated motion in 9. ________________________.

Everyday experience appears to support Aristotle's theory of horizontal motion on the Earth's surface. Moving things that are neither pushed or pulled come to a halt in a short amount of time. It appears like an object continues to move solely if a force acts on it. Is the natural state of an object to be at rest, and is a force necessary to keep an object in motion? This is exactly what people thought until Galileo published his book 10. _______________________ in 1638. Galileo presented an argument against Aristotle's view that a force is needed to keep an object in motion. He demonstrated that acceleration is caused by 11. ___________. Galileo concluded that bodies fall with a 12. ___________________ on the earth's surface, and that the force of gravity that causes all bodies to travel downward is a 13.______ _________________, based on the law of parabolic fall.

In the absence of air resistance, Galileo's law of free fall claims that all bodies fall at 14. ______________, regardless of mass. If Galileo were correct about the horizontal and vertical motions being independent, it would still continue to move 15. ________________ with a uniform, constant speed, but gravity would now begin to pull it down vertically at the same time, the distance increasing porportionally to the square of the time elapsed.

"Unless acted upon by an unbalanced force," Newton's first law of motion states, "an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction." Objects tend to "keep on doing what they're doing." 16. _______________ is the tendency for objects to resist changes in their state of motion. The resistance an object has to a change in its state of motion is known as inertia. The concept of inertia was created by Galileo. Moving objects eventually come to a halt due to a force called 17 __________. In experiments using a pair of inclined planes facing each other, Galileo observed that a ball would roll down one plane and up the opposite plane to 18. ________________. If smoother planes were used, the ball would roll up the opposite plane even closer to the original height. If friction is removed, the ball rolls to attain its original height, then this ball would never 19. _________.

All objects resist changes in their state of motion. Mass is that quantity that is solely dependent upon the inertia of an object. The greater the mass, the 20. ____________ the inertia.

parallel to the ground vertical direction inertia Two New Sciences Aristotle horizontally violent motion force natural motion the same exact height constant acceleration continue uniform motion constant force proportional the same rate inertia horizontal direction Aristotle stop greater