A 3 kg toy car is placed on a smooth wooden floor. The coefficient of static friction between the car and the floor is 0.12. What is the maximum static friction force that can act on the car before it starts moving?

Step-by-step solution

1. Step 1: Find the normal force. The car is on a horizontal surface, so $N=mg=3\times 10=30,\mathrm{N}$.
2. Step 2: Use the maximum static friction formula $f_{s,max}={\mu }_{s}N$. Plugging in ${\mu }_s=0.12$ gives $f_{s,max}=0.12\times 30=3.6,\mathrm{N}$.
3. Step 3: Conclude that $3.6,\mathrm{N}$ is the maximum static friction force before motion starts.

Concept tested: Maximum static friction force

Published 13 October 2026 · How this solution was prepared and checked