Why you slide backward when the wagon starts

Before this sitting

Can you already do this?

Two quick checks on “you will be able to…”. Right on both and this sitting becomes mixed practice, not a lecture. Wrong is useful — we keep the full sitting.

1. When the wagon starts, why do you feel like you fall backward?

   AA secret force pushes you backBYou keep sitting still while the wagon moves forwardCThe Earth stops pulling you downDWagons make a backward wind

2. A hockey puck on perfect ice (no friction, no air). What does it do?

   ASlow down because moving things get tiredBKeep sliding in a straight line at the same speedCStart spinning for no reasonDStop after ten seconds on its own