Name different types of friction. Explain …

There are four types of friction namely Static friction Kinetic friction Rolling friction Fluid friction Static Friction Static friction comes into play when a body is forced to move along a surface but movement does not start. The magnitude of static friction remains equal to the applied external force and the direction is always opposite to the direction of motion. The magnitude of static friction depends upon μs (coefficient of static friction) and N (net normal reaction of the body). Kinetic Friction Kinetic friction denoted as μk comes into play when a body just starts moving along a surface. When external applied force is sufficient to move a body along a surface then the force which opposes this motion is called as kinetic frictional force. Magnitude of kinetic frictional force fk = μk N Where μk is coefficient of kinetic frictional force and N is the net normal reaction on the body. The magnitude of kinetic frictional force is always less than magnitude of static frictional force. When value of applied net external force F is more than fk then body moves with a net acceleration and when these forces are equal then body moves with a constant velocity.