(a) To what angle \(\theta_{\max }\) does a coefficient of static friction of 1 correspond?

(b) Put, in turn, a coin, a paper clip, a cell phone, and a comb on the cover of this book and tilt the book to obtain the angle at which each object begins to slide. In each case, how close do you get to the angle calculated in part \(a\) ? What do you conclude from these observations about the coefficients of static friction for these combinations of surfaces?