Question

18 opción múltiple 1 punto
position (m)
time (sec)
when is the object moving in the positive direction?
for all 19 seconds shown
6-12.5 seconds
2-5 seconds and 12-14 seconds
5-7 seconds, 14-16 seconds, and 18-19 seconds

Explanation:

To determine when the object is moving in the positive direction, we analyze the position - time graph. The object moves in the positive direction when the slope of the position - time graph is positive (since the slope of a position - time graph represents velocity, and a positive slope means positive velocity, i.e., motion in the positive direction).

Step 1: Analyze the slope of each interval

• For the interval 0 - 2 seconds: The slope is 0 (the object is at rest).
• For the interval 2 - 5 seconds: The slope is negative (the object is moving in the negative direction as the position is decreasing).
• For the interval 5 - 7 seconds: The slope is positive (the position is increasing from - 3 m to 2 m).
• For the interval 7 - 12.5 seconds: The slope is 0 (the object is at rest as the position remains constant at 2 m).
• For the interval 12.5 - 14 seconds: The slope is negative (the position is decreasing from 2 m to - 6 m).
• For the interval 14 - 16 seconds: The slope is positive (the position is increasing from - 6 m to - 2 m).
• For the interval 16 - 18 seconds: The slope is 0 (the object is at rest as the position remains constant at - 2 m).
• For the interval 18 - 19 seconds: The slope is positive (the position is increasing from - 2 m to 0 m).

Answer:

5 - 7 seconds, 14 - 16 seconds, and 18 - 19 seconds (the option with this time interval)