CONTENT NOT ON NOTES PAGE
Ask if they’ve heard the word inertia. Stress they know what it is: running or driving fast (hard to stop), throwing a medicine ball, getting a cart or bike rolling.
FORCE: A PUSH OR PULL.
ETYMOLOGY: the word force comes from Latin fortis, 'strong'.
Inertia is not a force.
DEMO: push rolling cart, with rolling cart sitting on top.
DEMO: index card on top of glass, with quarter on top. Flick card aside, the quarter drops into the glass.
DEMO: pull tablecloth from under place setting. Try latter with objects of different coeffs of friction, and discuss briefly.
DEMO: airtrack and air hockey, or hovercraft disc.
DEMO: whiplash.
Philosophical discussion: we don't know why inertia happens.
DEMO: heavy weight hanging on thread, with another thread hanging below weight. Pull bottom thread slowly, and jerkily.