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
$\mu_{s} > \mu_{k} > \mu_{r}$