Question

extra practice problem #9
position vs. time
describe the time, speed, and direction of blue line based on this graph.
type here
describe the time, speed, and direction of purple line based on this graph.
type here

Explanation:

For the blue line:

1. From 0 to 5 seconds: The position decreases linearly from 10 m to 6 m, so it moves in the negative direction at a constant speed. The speed is calculated as $\frac{10-6}{5-0} = 0.8$ m/s.
2. From 5 to 10 seconds: The position stays constant at 6 m, so it is at rest (speed = 0).

For the purple line:
From 0 to 10 seconds, the position remains constant at 2 m, so it does not move at all (speed = 0, no direction of motion).

Answer:

1. Blue line description: First, it moves in the negative direction at a constant speed of 0.8 m/s for the first 5 seconds, then comes to a complete stop (speed = 0) and stays at 6 meters for the remaining 5 seconds.
2. Purple line description: This object is stationary (speed = 0) at a position of 2 meters for the entire 10-second interval, with no directional motion.