Demonstrates: Torque forces.

Description: A model ladder is placed against a box and a weight is moved up the ladder until the ladder begins to slip.

Demonstrates: Frictional Forces.

Description: A block with various surfaces is pulled with a spring scale.

Demonstrates: Angle of Repose.

Description: An incline plane is lifted until a block begins to slide.

Demonstrates: Distribution of Pressure.

Description: This video shows Dr. Wolfe demonstrating this concept.