why does the chalk flyoff if the hoop is hit on the outside in newtons first law?

Question

place a flexible card board in the hoop in the mouth of the bottle and center asmall piece of chalk/coin over the opening of the bottle and flick with your fingertip from under the chalk by hitting the hoop on the inside

Answer 1

See the ref. below. The hoop is balanced on edge on the bottle and the dropping object is balanced on the top edge. This version doesn't use a piece of cardboard, but I suppose it might be under the hoop and provide a nearly horizontal surface to skid the hoop out. Anyway, why does pulling the hoop out work better than pushing it out? One reason could be that when pulling something it tends to "follow" the pull, even if you're pulling slightly off-center. But if you push something off-center it will get more and more off-center as you continue. Another effect is related to the hoop's flexibility. When you put a horiontal force on one edge it will tend toward a more elliptical shape. Hit it on the inside (force outwards) and it will get wider and shorter (helping it avoid contact with the chalk). Hit it on the outside (force inwards) and it will get narrower and taller (more likely to hit the chalk as is moves sideways). This experiment illustrates Newton's 1st law, since when there is no sideways force put on the chalk it doesn't move sideways, and when there is, it does.

Answer 2

challenging problem. research over yahoo and bing. this could help!