The coefficient of friction is 0.75. If sin37º= 0.6, the angle of friction is

$\begin{array}{l}\mathrm{\mu }=0.75\\ \sin {37}^{\circ }=0.6=\frac{3}{5}\\ \tan {37}^{\circ }=\frac{3}{4}\\ \mathrm{\mu }=\tan {37}^{\circ }=\frac{3}{4}=0.75\\ \therefore \mathrm{\theta }={37}^{\circ }\\ \left(\mathrm{OR}\right)\\ \mathrm{\mu }=\tan \mathrm{\theta }\\ 0.75=\tan \mathrm{\theta }\Rightarrow \frac{\cancel{75}3}{\cancel{100}4}=\tan \mathrm{\theta }\Rightarrow \mathrm{\theta }={37}^{\circ }\end{array}$