An snowboard manufacturer wants to make the smoothest boards ever, she believes that can be achieved by reducing friction as much as possible. Describe 3 things that could be change on a board so that friction between it and the ice gets smaller.
A 1.5 kg book is held against a vertical wall. The coefficient of static friction is 0.65.
What is the minimum force that must be applied on the book, perpendicular to the wall, to prevent the book from slipping down the wall?