1. Chapter 12: Forces and Motion
Section 12.2
Newton’s First and Second Laws

2. Newton’s First Law of Motion
States that as long as the net force acting on an object equals zero there is no change in the motion of an object
Sometimes called the law of inertia
Inertia: tendency of an object to resist a change in its motion
Inertia can be measured by mass.

3. Newton’s Second Law of Motion
The acceleration of an object is equal to the net force acting on it divided by the object’s mass.
Acceleration = Net Force
Mass OR
a = F m

4. Mass and Weight Weight: force of gravity acting on an object
Weight = mass x acceleration due to gravity
W = mg
Things to note:
g = 9.8 m/s2
Weight is in Newtons.
Mass should be in kilograms.

5. Weight and Mass What is the difference between weight and mass?
Weight is a measure of the force of gravity on an object.
Mass is the measure of the inertia of an object.