6.12

Skip to 0 minutes and 9 secondsThis week we started to move but we could still apply statics because there were no accelerations. Well, to be precise, none in the direction we were travelling in. We still needed free-body diagrams, of course. You've encountered new forces and how engineers estimate them, such as rolling resistance and aerodynamic drag. When forces move, work is being done, and work leads us to power. Work and power normally wait for dynamics but you've learned enough to get the basic idea. Power is the mechanical engineers stock-in-trade. You've made a start in understanding it. Next week we'll end this course. You'll learn some dynamics and also how to play shove ha'penny.

Skip to 1 minute and 2 secondsEngineer's eyes will help you to understand shove ha'penny but they aren’t guaranteed to help you be more successful at it.

Through Engineers' Eyes

This quick video highlights your progress towards Engineers Eyes. The concept wheel shows how it all fits together.

Wheel revealing the words Week 4 2-foce objects, equivalent force systems, locating centres of gravity, Week 5 basic model of dry friction, friction and FBDs, managing dry friction-enough/too much, Week 6 modelling rolling friction, modelling aerodynamic drag, work and power Week 6 concept wheel (Click to expand)

Forces from wind were the main new forces here. As I write, northern Australia is beginning to clean up after a category 4 cyclone that left a trail of destruction behind it. But despite 250km/h gusts, modern, properly engineered buildings stood up well. Analysis plus experience no doubt made this possible.

Rolling resistance also appeared this week.

You calculated wind load and aerodynamic drag using a ‘beautiful equation’, and from these quantities calculated the power needed by an electric car - and its range.

To find power you needed to know about work. These concepts are more often found in Dynamics courses, but although we were beginning to break out from statics, we wouldn’t be free of its restrictions until week 7.

Talking points

These are to get you started. Share any other thoughts you’ve had.

  • What’s your reaction to ‘the equation for wind load is beautiful?’
  • We wanted to include power in this course because it can be thrilling. How does it seem to you?

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