Unit 1: Motion & Forces
- Model Page: The core lesson content. Start here to learn the concept.
- Guided Reasoning: A critical thinking companion. Use this to test your understanding and work through the logic of the physics.
Describing Motion Precisely
To understand physics, we must be specific. This lesson introduces the difference between distance and displacement, and how we measure movement using reference frames and vectors.
What Does Speed Really Measure?
Speed is more than “how fast.” This lesson focuses on what speed measures, what it ignores, and why choosing the right measurement matters.
Why Does Direction Matter?
Two motions can have the same speed but represent totally different movement. This lesson introduces direction as essential information, not a “detail.”
When Does Motion Change?
Motion changes when something causes it to change. This lesson focuses on what “change” means in motion and how we describe it consistently.
What Do Forces Actually Do?
Forces don’t “create motion” in a vague way—they cause specific changes. This lesson connects pushes and pulls to changes in how objects move.
Why Does Motion in the Real World Usually Stop?
If “things keep moving,” why do they stop? This lesson introduces the real-world effects that reduce motion and how we account for them in a model.
Why Do Objects Fall?
Falling looks simple, but it reveals a universal rule. This lesson introduces gravity as an interaction and clarifies what “down” means in a physical model.
How Do We Choose the Right Model?
Physics is model-building. This lesson shows how to decide which assumptions are reasonable and which details matter for the question you’re trying to answer.