Question

use the knowledge of effect of roughness on frictional force in day to day life​

Answer 1

Answer:

How does roughness affect friction?

Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.

Answer 2

Answer:

he relationship between normal force and friction force for a finger contacting a surface was examined, and also the effect of surface roughness, using a finger friction rig. To investigate the normal force–friction force relationship 12 materials were used: 3 metals, 5 plastics and 4 elastomers. Forty tests were carried out across a range of loads, for each material. The roughness tests were run on three metals (brass, steel and aluminium), with a range of surface roughness. The deformation of the finger was also monitored in the normal force tests using a high-speed video camera.The finger tested, reached a maximum area of contact at a low load: 1 N. Therefore, for forces above 1 N, the main friction mechanism was adhesion. The plateau in contact area and dominance of adhesion resulted in a linear relationship between normal force and friction force, for all loads above 1 N.The roughness tests showed that at a low surface roughness the finger dominates the interaction, so little difference is seen between materials and roughness. However, as the roughness increases the friction increases linearly, up to a point. At this point the friction does not vary as the width and height of the surface ridges are increased.

Explanation: