Tham khảo tài liệu 'science of everyday things vol. 2 - physics episode 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | FRICTION KEY TERMS ACCELERATION A change in velocity. COEFFICIENT OF FRICTION A figure constant for a particular pair of surfaces in contact that can be multiplied by the normal force between them to calculate the frictional force they experience. FORCE The product of mass multiplied by acceleration. FRICTION The force that resists motion when the surface of one object comes into contact with the surface of another. Varieties including sliding friction static friction and rolling friction. The degree of friction between two specific surfaces is proportional to coefficient of friction. FRICTIONAL FORCE The force necessary to set an object in motion or to keep it in motion equal to normal force multiplied by coefficient of friction. INERTIA The tendency of an object in motion to remain in motion and of an object at rest to remain at rest. MASS A measure of inertia indicating the resistance of an object to a change in its motion including a change in velocity. MECHANICAL ADVANTAGE The ratio of force output to force input in a machine. NORMAL FORCE The perpendicular force with which two objects press against one another. On a plane without any incline which would add acceleration in addition to that of gravity normal force is the same as weight. ROLLING FRICTION The frictional resistance that a circular object experiences when it rolls over a relatively smooth flat surface. With a coefficient of friction much smaller than that of sliding friction rolling friction involves by far the least amount of resistance among the three varieties of friction. SLIDING FRICTION The frictional resistance experienced by a body in motion. Here the coefficient of friction is greater than that for rolling friction but less than for static friction. SPEED The rate at which the position of an object changes over a given period of time. STATIC FRICTION The frictional resistance that a stationary object must overcome before it can go into motion. Its coefficient of friction is greater than .
