Skip to 0 minutes and 9 secondsLike any other force, friction is not revealed until the body it acts upon is abstracted by a free-body diagram. As forces go, friction is particularly mysterious. But for practical purposes, we can represent its behaviour pretty well by the simple model we developed this week. As you develop engineer's eyes, you'll see friction acting all around you. And you will see the characteristics we have explored in the model. As your car breaks to a halt with a jerk at the last moment, you'll think of the transition from kinetic friction to static friction. And as you try to push a fridge along the floor without it toppling, you'll think of the analysis that we have undertaken in this week.

Skip to 0 minutes and 59 secondsYou'll notice how many turns the deckhand takes with the mooring rope around the bollard to secure a ferry to the wharf. And you might wonder if that squeal from the engine bay of your car is telling you that there's not enough tension on the belt drive to the air conditioner. Yes, there are engineer's ears as well. Next week, it's rolling resistance and wind loading.

Through Engineers' Eyes

You are on your way towards gaining ‘engineers’ eyes’.

This short video explains what you have encountered and what is to come.

Talking points

  • How are you getting on with the course so far?
  • These experiments were simple. How many of them did you try?
  • Were you able to access the exponential function on your calculator?
  • Do you see beauty and mystery in the equation for the ratio of tensions in a rope around a bollard?
  • We have said that ‘the Engineers’ basic model of friction is rough and ready but nevertheless useful’. What do you think about this statement?

Share your experiments

Don’t forget to share your experiments on the Through Engineers’ Eyes Padlet wall for this week.

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This video is from the free online course:

Through Engineers' Eyes: Engineering Mechanics by Experiment, Analysis and Design

UNSW Sydney