there are various methods to reduce friction, like: 1. Polishing the surfaces2. Adding lubricants3. increasing the temperature4. wetting the surface5. removing impurities, etc. :)
Depends what you want to increase/decrease friction on. If is like a weight on the floor.. Then to increase the friction all you have to do is increase the weight, To reduce it you either reduce the...
Between two rigid objects: Increase the surface area that is in contact between the two objects Increase the roughness of the surfaces in contact Increase the relative speed of the two objects...