Question

Which is true for rolling friction $\left({\mu }_r\right)$, static friction $\left({\mu }_s\right)$ and kinetic friction $\left({\mu }_k\right)$ :

• A. ${\mu }_s>{\mu }_k>{\mu }_r$
• B. ${\mu }_s<{\mu }_k<{\mu }_r$
• C. ${\mu }_s<{\mu }_k>{\mu }_r$
• D. ${\mu }_s>{\mu }_r>{\mu }_k$

Answer 1

Answer: (A)

Static friction is always greater than kinetic friction, and rolling friction is less than kinetic friction, so
${\mu }_s>{\mu }_k>{\mu }_r$