Why do this problem?

This problem is great for stimulating discussion at the start of a mechanics course.

Possible approach

This problem is easy to introduce to a class according to the order suggested in the problem, but you might like to keep the existence of the Gombocs as a surprise. As you lead the exploration, be on the lookout for opportunities to introduce and reinforce key concepts and vocabulary as students strive to articulate their thoughts. Examples might include: uniform density; equilibrium; perturbation; stability; symmetry; mathematical model; configuration; static; centre of mass; magnitude; vectors and forces. Preparing the ground in this way before rushing into content is time well spent!

Throughout, demand clarity of thought and speech.

Key questions

Possible extension

Possible support