A motion map for a motorcycle is shown.

Question

A long black arrow pointed right labeled x. Above that are two green arrows with the second shorter than the first pointed right. Above the green arrows are two yellow of equal length pointing left. Further above are two dots. Above that are two green arrows pointing right with the second on longer. Above that are two small yellow arrows pointing right.
At which second does the motorcycle start to have positive acceleration?

1
2
3
4

Answer 1

To determine when the motorcycle starts to have positive acceleration based on the description of the motion map:

1. Understand the arrows: The length of arrows indicates the speed (longer arrows mean faster speed) and the direction of arrows indicates the direction of motion.
2. Acceleration: Positive acceleration occurs when the speed of the motorcycle is increasing in the direction of motion (right in this case).

From your description:

• At 1 second, the first green arrow is longer than the second green arrow, indicating a decrease in speed.
• At 2 seconds, it's similar; the second green arrow is even shorter than the first green arrow.
• At 3 seconds, the motorcycle seems to be slower still, since it’s indicated by two small yellow arrows pointing right.
• Finally, at 4 seconds, the green arrows point right, with the second one being longer than the first, indicating that the motorcycle is speeding up again.

Therefore, the motorcycle starts to have positive acceleration at 4 seconds.