1. Topic: Newton’s 2nd Law of Motion
Notes
When the forces acting on an object are not balanced, the object will accelerate in the direction of the net force.
Acceleration is the rate of change of an object’s velocity. The acceleration of an object requires an unbalanced force. The acceleration of an object is directly proportional to the force applied to it and inversely proportional to the mass of the object.
Questions What is Newton’s 2nd Law? How can I restate Newton’s 2nd Law?
A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects.
All objects resist changes in their state of motion - they tend to "keep on doing what they're doing."

2. Topic: Newton’s 2nd Law of Motion
Notes
Imagine a physics book at rest on a table (the net force on the book is 0). However, there are two forces acting on the book: Earth's gravitational pull (downward force) and an upward push from the table (the normal force).
If you dropped the book from the height of the table it would accelerate towards the ground.
Note: After landing on the floor, the normal force (an upward push) would balance the downward pull of gravity and the object would no longer accelerate (and the net force would be back to 0).
Questions What is an example of an object with balanced forces acting on it? What is an example of an object with unbalanced forces acting on it?
A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects.
All objects resist changes in their state of motion - they tend to "keep on doing what they're doing."

3. Balanced vs. Unbalanced
Balanced Forces
the net force is 0, meaning the object will not accelerate
Unbalanced Forces
the net force is directed downward, meaning the object will accelerate in that direction
Normal
Gravity
Gravity