Learning Targets
- Describe where friction appears in a moving mechanism.
- Explain when friction is useful and when it causes performance problems.
- Recommend a design adjustment to improve reliability.
IED Unit 4 • Lesson 4.7
Friction, Force, and Mechanism Performance
Focus question: How does friction affect whether a mechanism works reliably?
Mission Briefing
Today’s Plan
Use this page with the lesson presentation, your engineering notebook, and the tools or evidence assigned for Investigate Friction and Mechanism Performance.
Success Looks Like
You can explain how friction can help or hurt mechanism performance and propose a design adjustment.
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Opening Prompt
How does friction affect whether a mechanism works reliably?
Connect your response to the decision, evidence, or quality standard required for Investigate Friction and Mechanism Performance.
Reveal: useful engineering move
This lesson is ready to move forward when the evidence meets this standard: The conclusion identifies the tested condition and does not confuse friction with an unrelated design change.
Core Skill
What We Are Practicing
Friction can provide grip, resistance, or unwanted energy loss.
Mechanism performance depends on contact surfaces, alignment, force, and material choice.
A friction problem should be diagnosed before parts are redesigned.
Your Task
Investigate Friction and Mechanism Performance
Compare mechanism performance under different contact, load, or lubrication conditions using a controlled test.
- Define the performance measure to observe.
- Change only the assigned friction-related condition.
- Record force, travel, time, or qualitative behavior consistently.
- Explain how friction helped or harmed performance.
Quality check: The conclusion identifies the tested condition and does not confuse friction with an unrelated design change.
Lesson Interactive
Estimate Friction in a Sliding Guide
Calculate friction force and decide whether the design should increase or reduce it.
Estimated friction force
Use Ffriction = μN.
Set the given test values and choose a response that supports smooth sliding motion.
What You Will Submit
Friction Test Evidence
Submission standard: The conclusion identifies the tested condition and does not confuse friction with an unrelated design change.
Resources
Lesson Resources
Lesson 4.7 PowerPoint
Use the lesson slides for guided practice, interactive checks, and the exit ticket.
Introduction to Engineering Design
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