38.(Pg. [40]) What is the result if the balls are not elastic, and how is this explained by [fig. 5]?
39.(Pg. [40]) How will reaction assist us in explaining the flight of a bird?
40.(Pg. [40]) How must their wings operate in enabling them to remain stationary, to rise, and to descend?
41.(Pg. [41]) Why cannot a man fly by the aid of wings?
42.(Pg. [41]) How does reaction operate in enabling us to swim, or to row a boat?
43.(Pg. [41]) What constitutes elasticity?
44.(Pg. [41]) Give some examples.
45.(Pg. [41]) What name is given to air, and for what reason?
46.(Pg. [41]) What hard bodies are mentioned as elastic?
47.(Pg. [41]) Do elastic bodies exhibit any indentation after a blow? and why not?