The velocity-time graph below shows the motion of a bushwalker in the Blue Mountains over 10 seconds. Using the graph, (i) determine the acceleration during the first 4 seconds, (ii) calculate the total displacement over the full 10 seconds, and (iii) explain what the shape of the graph between t = 4 s and t = 10 s tells us about the net force on the bushwalker during that interval.

The image shows a graph with text and numbers on it, surrounded by plants and rocks, with hills in the background and a sky with clouds. The text on the graph reads "the dewhains if the blue musthains".