Choose helpful axes
Separate directions parallel and perpendicular to the ramp.
AP Physics 1 · Unit 2, Part 1 · Forces
Inclined Planes
Tilt a ramp, resolve the weight, and connect force components with the block’s acceleration and motion.
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- Self-paced
Start guided lesson
Learn by doing
Three ideas you’ll put into motion
Test the angle
Change the incline angle and compare the downhill acceleration.
Connect force and motion
Use a force model and the recorded slide to check a prediction.
The big idea
The key ideas, at a glance.
Weight stays vertical
Gravity acts downward, even when the axes rotate. Its downhill component is mg sin θ and its into-ramp component is mg cos θ.
The normal force is perpendicular
For a supported block with no other perpendicular forces, N = mg cos θ. The downhill force model also includes friction when present.
A quick comparison
Increase the angle of a frictionless ramp, keeping the block supported.
Downhill acceleration increases.
Teaching this topic?Classroom fit, AP connections, and support
- Classroom fit
- Use for a concept introduction, guided independent practice, or a projected class discussion.
- Before students begin
- Free-body diagrams, Newton’s second law, and basic sine and cosine.
- Built-in support
- Prepared scenes, guided prompts, and feedback on lesson questions.
- AP Physics 1 connections
- Unit 2: force components, ramp motion, and system modeling.
- Check for understanding
- Ask why the normal force is usually smaller than mg on a simple incline.
- Optional extension
- Investigate further with the Inclined Plane lab.
Ready to test your thinking?
The first scene is set up. Start the lesson and explore.