- Friction prevents the metal washer on incline from slipping. Washer will begin to slide down plane when angle is great enough (one can show that the coefficient of friction is equal to the tangent of the angle when the washer just begins to slip). Materials include: rubber, glass, wood, and teflon.
- Use angle ruler (shown in photo) to measure angle.
- Materials located in L02, section B3. Angle ruler in L45, with rulers.