Question

Find minimum normal force to be applied by each hand to hold three identical books in a vertical position. Each book in a vertical position. Each book has mass m and the value of the coefficient of friction between the books as well as between hand the book is $\mu$.

Answer 1

For each book to be in equilibrium

$2f=mg$.

$f=\frac{mg}{2}$.

$\mu N=\frac{mg}{2}$

$N=\frac{mg}{2\mu }$