Question

If the road of the previous problem is horizontal (no banking), what should be the minimum friction coefficient so that scooter going at 18 km/hr does not skid?

Answer 1

If the road is horizontal (no banking), we have:
$$\begin{gathered} \frac{m{v}^2}{R}=f_s \\ N=mg \end{gathered}$$
Here, f_s is the force of friction and N is the normal reaction.
If μ is the friction coefficient, we have:
$$\begin{gathered} \mathrm{Friction}\mathrm{force}=f_s=\mu N \\ \mathrm{So},\frac{m{v}^2}{R}=\mu mg \end{gathered}$$

Here,
Velocity = v = 5 m/s
Radius = R = 10 m
$$\begin{gathered} \therefore \frac{25}{10}=\mu g \\ \Rightarrow \mu =\left(\frac{25}{100}\right)=0.25 \end{gathered}$$