1' draw a displacement -time graph for the following. displacement (m) 0,20,40,40,80,80,60,40 time (s) 0,10,20,30,40,50,60,70,80. a) explain the different sections of the graph in as much detail as you can. b). use the graph to determine the maximum velocity c) find the average velocity after 45s. d) find the instantaneous velocity at 45s ​