Friction is a force that opposes motion. It is present whenever two surfaces rub over each other, such as when you rub your hands together, or when you apply the brakes on a bike or in a car. Friction ...

Friction is responsible for about twenty percent of the world energy consumption. The main reason for this is that frictional forces slow down the motion of surfaces in contact: think of the moving ...

Turning 75 is a deal big enough to demand some serious gifts. Over the past three years, Walker Art Center staff solicited art in honor of the museum's 1940 rebranding as a contemporary art center.