Unit B is about 25% of the Physics 20 course. This is equivalent to approximately 20 80-minute classes. You may have to do additional “homework” hours to complete this unit.
In Unit B you will investigate the causes of changes in the velocity of objects and systems. In effect, you will study dynamics and gravitation. You will be introduced to the concepts of gravitational fields to explain gravitational effects. This unit will prepare you for further study of Newton’s laws and periodic motion and electric and magnetic fields.
In Module 3 you will look at non-zero (unbalanced) net force and their effect on velocity. You will examine Newton’s first law of motion to help you understand the forces acting on an object at rest and an object with uniform motion. Newton’s second law of motion will help explain the relationships among net force, mass, and acceleration. You will apply Newton’s third law of motion to interactions between two objects. You will examine the differences between static and kinetic forces of friction. You will apply vector tools from Unit A to calculate the resultant force acting on an object, and you will apply Newton’s laws of motion to solve linear-motion problems in horizontal, vertical, and inclined planes near the surface of Earth.
In Module 4 you will see that the gravitational force is one of the fundamental forces in nature. You will examine the principles of the Cavendish experiment and study Newton’s law of universal gravitation. You will relate the gravitational constant to the local value of the acceleration due to gravity. You will predict differences in weights of objects on different planets.
By the end of this unit, you will be able to explain the effects of balanced and unbalanced forces on velocity and explain that gravitational effects extend throughout the universe.
Think about the following questions as you complete this unit:
Once you have completed this unit, you will have a Unit B Assessment to complete. The Unit B Assessment is a diploma-examination type of question. It will require you to use the entire set of tools that are introduced and worked with in this unit.