1.1 What is friction? Take this everyday example: when a coffee mug rests on a flat table, the kinetic frictional force is zero. There is no force trying to move the mug across the table, so there is ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Friction is a force that exists when two surfaces rub up against each other. For example, this cup on ...

• Excessive seal friction wastes energy, accelerates wear, and can lead to premature failure. • Too little friction makes a seal prone to leak. • Pressure-activated hydraulic seals minimize both ...