Question

use this graph below for this question
position of a runner moving in a straight line
graph
when is the runner moving in the negative/backwards direction and toward their starting location?
⦿
a between 80-104 seconds
r between 80-110 seconds
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Explanation:

To determine when the runner moves backward toward the starting location, we analyze the position - time graph. The slope of a position - time graph represents velocity. A negative slope (downward - sloping line segment) indicates motion in the negative/backward direction.

• First, observe the graph: From 0 to 70 seconds, the slope is positive (runner moving forward). From 70 - 80 seconds, the slope is 0 (runner at rest).
• Then, look at the time intervals for the negative slope: The segment with negative slope (backward motion) starts at 80 seconds. We need to find when the runner reaches the starting location (position 0, assuming the y - axis represents position relative to start). By looking at the graph, the runner reaches the starting location at 110 seconds (since the position is back to the initial value at 110s). So the time when the runner is moving backward toward the start is between 80 - 110 seconds. Option A (80 - 104s) would mean the runner hasn't reached the start yet, while option R (80 - 110s) includes the time until the runner gets back to the start.

Answer:

R. Between 80 - 110 seconds