Apologia Physical Science Lesson 3-- Module 11

Kon'nichiwa, guys! Olydia here again! Today we'll be doing another lesson from our Apologia Physical Science book, Module 11. Our topics today are:

• The Four Fundamental Forces of Creation
• Gravitational Force
• Force and Circular motion
• Fictional Force
• Gravitational Force in our Solar System
• Comets, Meteors, Meteorites, and Meteoroids
• What Causes Gravitational Force

Let's start!

1. The Four Fundamental Forces of Creation. The four fundamental forces are gravitational, electromagnetic, weak force, and strong force. They're called fundamental forces because all force is traced back to one of these four forces. 

2. Gravitational force is the easiest force to recognize. Gravity is everywhere on earth. It may seem easy, but it's hard to understand. Scientists aren't exactly sure what causes it. When an apple falls off of a tree, it doesn't actually fall, it is pulled by gravity to the ground. The three general principles of the Universal Law of Gravitation are: 

a) All objects with mass are attracted to one another by the gravitation force. 

b) The gravitational force between two masses is directly proportional to the mass of each object.

c) The gravitational force between two masses is inversely proportional to the square of the distance between those two objects.

3. Force and Circular Motion. Circular motion requires a special force, which is centripetal force. Centripetal force is the force necessary to make an object move in a circle. It is directed perpendicular to the velocity of the object, which means it points toward the center of the circle. There'll be a video below with an experiment using centripetal force and circular motion.

4. Fictional Force.