Explore how forces and friction work to hold a block against a vertical wall. This video explains normal force, frictional force, and equilibrium conditions, showing how these forces balance to ...

In "Friction," tribologist Jennifer Vail shows how the fundamental force that resists motion keeps driving us forward.

Friction is an intrinsic physical phenomenon to curling. Without it, objects in motion would move endlessly, without slowing down. This would cause many safety-related problems: Cars or trains could ...