Dissemination of IT for the Promotion of Materials Science (DoITPoMS)



Quick questions

You should be able to answer these questions without too much difficulty after studying this TLP. If not, then you should go through it again!

  1. Which of the following correctly describe lubricants? (You may pick more than one answer)

    a Decrease μ
    b Decrease the extent of wear
    c Are always liquids
    d Always completely separate the surfaces / prevent asperity formation

  2. μ depends on… (You may pick more than one answer)

    a Apparent area of contact
    b Normal load
    c Sliding velocity
    d All of the above

  3. The Archard equation is useful because it provides a measure of… (You may pick more than one answer)

    a The severity of wear
    b Viscosity index
    c Surface roughness
    d The shear strength of a lubricant

  4. When skis move over snow sliding takes place over a thin film of water on top of the snow giving a low μ. This is because

    a a pressure-induced solid → iquid phase transformation occurs
    b snow melts because of the dissipation of heat due frictional work

  5. The coefficient of friction between two given materials is constant.

    a True
    b False

Deeper questions

The following questions require some thought and reaching the answer may require you to think beyond the contents of this TLP.

  1. Geckos are able to climb vertical walls. Can they do this using only frictional forces?