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A Level Mechanics
Friction
Learn friction as part of model motion, forces, moments, friction, projectiles and variable acceleration.
Key idea
Draw a model first, define the direction of motion, then choose the equation that matches the known quantities.
What you will learn
Use friction meaning confidently.
Use friction representations confidently.
Use friction methods confidently.
Use friction applications confidently.
Success checklist
āI can explain what friction means.
āI can choose a suitable method without being told.
āI can show clear working and check my answer.
Worked example
A particle starts from rest and accelerates at 2 š/š Ā² for 5 s. Find š£.
Step 1
Use š£ = š¢ + šš”.
Step 2
Here š¢ = 0, š = 2 and š” = 5.
Step 3
š£ = 0 + 2 Ć 5 = 10.
Answer
10 š/š
Quick practice
Question 1
Find F when š = 4 kg and š = 3 š/š Ā².
Question 2
Find the moment of a 10 N force acting 0.4 m from a pivot.
Question 3
State the initial vertical velocity for a horizontal projectile.
Related resources
These are linked to the wider Mechanics topic for now.