Question

position vs. time
which object moves at a slower speed?
the object represented by line a (red).
the object represented by line b (blue).
both objects have the same speed.

Explanation:

Step1: Define speed from position-time graph

Speed is the magnitude of the slope of a position-time graph, calculated as $\text{speed} = \frac{\Delta \text{position}}{\Delta \text{time}}$.

Step2: Calculate speed for Line A

For Line A: at $t=10\ \text{s}$, position $x=0\ \text{m}$ (stays at origin).
$\text{Speed}_A = \frac{0 - 0}{10 - 0} = 0\ \text{m/s}$

Step3: Calculate speed for Line B

For Line B: at $t=10\ \text{s}$, position $x=8\ \text{m}$; at $t=0\ \text{s}$, $x=0\ \text{m}$.
$\text{Speed}_B = \frac{8 - 0}{10 - 0} = 0.8\ \text{m/s}$

Step4: Compare speeds

$\text{Speed}_A = 0\ \text{m/s} < \text{Speed}_B = 0.8\ \text{m/s}$, so Line A's object is slower.

Answer:

The object represented by line A (red).