Consider the different paths the man wolkes and ran. Each path can be drawn as a line in a graph.
- Tree to the house
- House to the tree
- Man stops to repair the lawn mover
- Tree to the house but faster
The graph which represents the previous situation is as follow:
Assume that the position of the tree is for x = 0. Then while t increases (time passes) man goes to the house (first line), then he comes back to the tree (second line). Next, he stops (horizontal line, only ti increases, x does not change). And finally, the man run very fast to the house (four line). The last line has greater slope respect to the first line because the slope is related to the speed .