Question

A motion map for a motorcycle is shown.

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

4

Explanation: positive acceleration means the velocity is increasing in the +x direction. The map shows right-pointing velocity arrows that get longer (speeding up to the right) at the fourth interval, so acceleration becomes positive at second 4.