3.2.6—Toppling and sliding

A body slides when the available friction is insufficient for equilibrium; it topples when the line of action of the resultant reaction moves beyond the supporting base. Both are checked after force and moment balance.

Find the friction required and compare it with μR for sliding. For toppling, take moments about the edge that would become the pivot and set the limiting reaction there to zero.

A crate on a rough floor may remain at rest while a horizontal force increases. If the force line creates a moment that lifts one edge first, toppling occurs before the friction limit is reached.

A large friction coefficient does not prevent toppling, and “about to topple” does not mean the body has already started rotating.