Newton’s Laws of Motion and 2D Applications

In this lesson on Newton’s Laws of Motion and 2D Applications, which is part of Unit 3 Area of Study 3 for VCE Physics, you will learn how to:

investigate and apply theoretically and practically Newton’s three laws of motion in situations where two or more coplanar forces act along a straight line and in two dimensions.

What are Newton’s Laws of Motion?

Newton’s Laws of Motion are:

Inertia: An object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.
$F = ma$ : The velocity of an object changes when it is subjected to an external force. For an object with a constant mass $m$ , the second law states that the force $F$ is the product of an object’s mass and its acceleration $a$ .
For every action (force) in nature, there is an equal and opposite reaction.

The following videos go further in-depth about what Newton’s Laws of Motion are, and why they are significant in describing static and dynamic interactions.

Part 1: Crash Course Newton’s Laws

Part 2: Static and dynamic interactions

How do we solve problems involving resultant and component forces?

To solve problems involving resultant and component forces, we apply the following relationships:

$\vec{F}_{AB} = -\vec{F}_{BA}$
$F_{x} = Fcos(\theta), F_{y} = Fsin(\theta)$

The following video covers a step-by-step approach in solving problems that involve resultant and component forces. It will go more in-depth on inclined plane forces components.