18.(Pg. [35]) If gravity did not draw a projected body towards the earth, and the resistance of the air were removed, what would be the consequence?
19.(Pg. [35]) In this case would not a great degree of force be required to produce a continued motion?
20.(Pg. [35]) What is retarded motion?
21.(Pg. [35]) Give some examples.
22.(Pg. [36]) What is accelerated motion?
23.(Pg. [36]) Give an example.
24.(Pg. [36]) Explain the mode in which gravity operates in producing this effect.
25.(Pg. [37]) What number of feet will a heavy body descend in the first second of its fall, and at what rate will its velocity increase?
26.(Pg. [37]) What is the difference in the time of the ascent and descent, of a stone, or other body thrown upwards?
27.(Pg. [37]) By what reasoning is it proved that there is no difference?