What is the coefficient of static friction? And why does it matter?
The coefficient of friction is the ratio of the force needed to push an object and make it slide divided by the force downward on the object (e.g., weight) resisting motion. It is used to determine the amount of force that is needed to make a smooth surfaced object of one material slide on a smooth surface of the same or a different material. For every combination of materials there is a specific coefficient of friction. Once calculated, the coefficient can be used for various loads (size of object). Ice on teflon has one of the lowest coefficients of friction. If you place an object on a plank and raise one end almost every object will slide before you reach an angle of 45 degrees. Objects that have an adhesive property or are especially rough or have cogs will not have true coefficients of friction. Once the coefficient of friction is known for a combination of materials (e.g., as determined in a lab) it can be used in many mechanical calculations where friction is present although t
