Question

which line has the faster speed? which line shows the runner resting? what was the average speed of runner b? distance - time graph distance (meters) time (seconds)

Explanation:

Step1: Recall speed - distance - time relationship

Speed is calculated as $v=\frac{d}{t}$, where $v$ is speed, $d$ is distance and $t$ is time. On a distance - time graph, the slope of the line represents the speed.

Step2: Analyze the graph for runner B (line B)

For runner B (line B), assume it travels a distance $d = 200$ meters in time $t= 50$ seconds. Using the speed formula $v=\frac{d}{t}$, we have $v=\frac{200}{50}=4$ m/s.

Step3: Determine resting condition

A runner is resting when there is no change in distance over time, i.e., the slope of the line on the distance - time graph is 0. Line C has a horizontal section where the distance does not change with time, so line C shows the runner resting.

Step4: Compare speeds

The steeper the line on a distance - time graph, the greater the speed. Line B is steeper than line A, so line B has the faster speed.

Answer:

a. 4 m/s
b. C
c. B