1. Newton’s Three Laws of Motion
Dynamics
Newton’s Three Laws of Motion

2. Forces We have learned that forces either pushes or pulls.
They come in many varieties:
Gravity & Normal
Kinetic & Static Friction
Electrical & Magnetic
Air resistance
Tension
Nuclear Force
And many more…

3. Newton’s Three Laws
Sir Isaac Newton did not only develop the law of universal gravity.
He also developed the three laws which describe the motion of all objects in the universe.
These laws form the basis of Newtonian Mechanics.

4. First Law: The Law of Inertia
“An object remains at rest or in a state of constant motion unless acted upon by an unbalanced external force.”
The heavier an object is, the harder it is to change it’s motion. This resistance to a change in motion is called inertia.

5. Eg.1: A car skidding off of a curved icy road.
As the car attempts to turn, the wheels fail to change the direction because of the lack of friction.
The car continues in its straight line until it hits the ditch.
Large mass = large inertia
Small mass = small inertia

6. Newton’s Second Law
“In the presence of an unbalanced external force, an object will accelerate in the direction of that force”.
This acceleration is inversely proportional to the object’s mass
i.e: The heavier the body, the smaller the acceleration.
Written as:
Where:
F = Net Force (N)
m = mass (kg)
a = acceleration (m/s2)

7. Eg.2: Find the net force acting on a 10kg object that is accelerating at 5.0 m/s2
Eg.3: Find the acceleration of a 15kg object that is experiencing a net force of 30N [R]