AbstractFrictional laws govern the way humans interact with their surroundings in all aspects of daily life. This research project serves to investigate the effects of friction with respect to their occurrence in daily life, i.e. in situations where the forces of friction may be important , especially with regard to safety.

Friction: What is it?

When an object is in motion on a surface, it

encounters resistance due to the way it reacts with its

environment. We call this resistance the “Force of

friction”. Frictional force may be determined by

multiplying the normal force (n) exerted on the

surface (weight force), by a Coefficient of Friction

(where is the Coefficient of static friction).

Unfortunately, Coefficients of friction vary upon the

materials in contact and therefore are not “set

values”. Coefficients of friction must be determined

empirically.

Project ObjectiveTo compare the coefficients of friction between two

different Groups of common surfaces found in

practical usage. The surfaces will be tested under

different conditions.

Results of

Experimentation/Research

1. Group I Surfaces (Tiles): A common surface choicefor flooring in most buildings. The following graphshows the variation of the Coefficient of Staticfriction for different tile types under both wet ordry conditions.

2. Group II Surfaces (Other): Two other commonsurfaces utilized in most building applications areAsphalt and Concrete. The following graph shows thevariation of the Coefficient of Static friction for thesesurface materials, both wet and dry.

Discussion of resultsThe Coefficient of static friction was observed to suffer

drastically under wet conditions. This is intuitively accurate

as no doubt most people are wary of how slippery ceramic

tiles are when they are wet. In this case the rougher tiles

performed better and therefore would be considered safer

to use under both wet and dry conditions. It as also

interesting to observe that the coefficient of friction for

plain concrete was greater than that of Asphalt under both

wet and dry conditions. This may be misleading though as

Asphalt is the better choice of road surface for car tire

rubber. This may be due to the different treatment car-tire

rubber undergoes during manufacturing processes.

RecommendationAfter analyzing the results obtained by experimentation

with different surface materials, it is reasonable to

recommend that rougher tiles be used for flooring

purposes, especially in outdoor conditions. Also, concrete

would be the best choice of material for outdoor pathways

as well as sheltered pathways which are of considerable

length. This would provide a much safer walking surface

for rubber soled shoes.

ReferencesSerway, R., & Jewett, J. (2010). Physics for Scientists andengineers. Belmont: Mary Finch.

Fig. 1 Frictional Force

Applications of Frictional ForceSchool of Engineering and Physics, USP

MM103: ENGINEERING MECH. MINI PROJECT POSTER…

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Concrete-Rubber Asphalt-Rubber

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ConclusionIn hindsight, it may be safely concluded that the

objectives of the project were fully met, as the

frictional coefficients of different surfaces under

varying conditions were successfully compared. Also

evidence based recommendations were made on the

optimal choice of surface material with a view to

safety.

Interesting note on FrictionContrary to popular belief, surface roughness is only

a minor contributing factor to friction. In actuality

Friction is often higher between smoother surfaces.

E.g. Insects can walk on glass windows, an extremely

smooth material.

Rajneel Sharma (S11075328), Milika Vucago (S11069516), Ryan Bale (S11078457)