If the externally applied force F just equals the force of kinetic friction, Fk, then the object slides at a constant velocity, and the coefficient of friction involved is called the coefficient of kinetic friction, μk .

Direction. Kinetic friction is always directed opposite to the direction of the velocity of the object measured relative to the surface (i.e. in the reference frame moving with the surface).

Friction is independent of the area of contact so long as there is an area of contact. The coefficient of static friction is slightly greater than the coefficient of kinetic friction. rge limits, kinetic friction is independent of velocity. Friction depends upon the nature of the surfaces in contact.

You can use rollers to move a heavy object along the ground, since they reduce the resistance from friction. Rolling friction is much less than sliding friction.

Why is the object quicker to slow down on carpet than on the bare floor? Carpet has a rougher surface than the bare floor, so there are more areas for the object to have friction with the rougher surface and slow down.

Reducing Friction There are several ways to reduce friction: The use of bearing surfaces that are themselves sacrificial, such as low shear materials, of which lead/copper journal bearings are an example. Replace sliding friction with rolling element friction, such as with the use of rolling element bearings.

It will travel much further on the smooth surface because there is less friction.

Rougher surfaces have more friction between them than smoother surfaces. That’s why we put sand on icy sidewalks and roads. You can’t slide as far across ice with shoes as you can on the blades of skates (see Figure below). The rougher surface of the soles of the shoes causes more friction and slows you down.