What friction is in terms of energy losses from a system Friction: energy→heat How friction arises in machines (gears, shafts etc) How to reduce friction in machines (lubrication, choosing different materials etc) How to draw a force diagram for friction (mention - go more in-depth into force diagrams later)?
Who can get the best block slider? Or, redesign catapults to include low-friction.
Have to connect this to energy losses. Talk first about force and momentum, then talk about friction? how do we connect this to other things?
Force diagrams…
little cars…climbing hills vs sliding down hills? Friction good vs friction bad?
Energy lost to heat - feel things, feel them to be hotter? Concept of energy, arge. It's more difficult to pull things up hills.
Can we use the springs from last time?