4.16

Skip to 0 minutes and 10 secondsGravity can be a help or a hindrance. Either way, it must be incorporated into our free-body diagrams. If we are talking particles, we need only know the magnitude of the force that gravity produces. When we are talking rigid bodies, we need to know where a gravity force acts, because where it acts determines the twisting effect - as seen in our free-body diagrams - and these determine the distribution of forces. For shapes like squares or spheres or cubes, we can see that the centre of gravity is in the geometric centre. But what of more complicated shapes? Splitting up a composite shape into simple elements gives us a way of finding its centre of gravity. A table can be a big help.

Skip to 1 minute and 5 secondsWe saw the importance of load distribution - and hence, location of centre of gravity - in aircraft, not that it bothered conceptual artist, Panamarenko, beside his flying wing in SMAK, the Municipal Museum of Contemporary Art in Ghent, in Belgium. The description read, "Panamarenko started building Utopian aircraft in the 1960s. His quest for air-worthy constructions never resulted in functional machines." The possibility of failure is an inseparable part of his work, and gives it its poetic eloquence - so different from engineers' eyes. Gravity is the most basic of loads. The next load we'll consider is friction.

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.

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This video is from the free online course:

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

UNSW Sydney