Lesson 1 of 3

Forces and Vectors

Understand what a force is and how to represent it as a vector.

What is a force?

A force is a push or pull that can cause an object to accelerate, deform, or change direction. Forces are vectors - they have both magnitude and direction.

Representing forces

We typically represent a force with:

  • A magnitude (e.g. 100 N)
  • A direction (e.g. 30° above horizontal)

Resolving into components

Any 2D force can be broken into horizontal and vertical components:

Fx = F · cos(θ)
Fy = F · sin(θ)

This is the single most useful skill in statics. Once forces are in component form, you can add them algebraically.

Practice

Try resolving a 200 N force acting at 45°:

Fx = 200 · cos(45°) ≈ 141.4 N
Fy = 200 · sin(45°) ≈ 141.4 N

Next up: combining forces and finding resultants.