Question

during which time interval was the motion fastest?
1 h to 2 h
2 h to 3 h
3 h to 4 h
4 h to 5 h
displacement vs. time for a car
displacement (km)

Explanation:

Step1: Recall speed - slope relation

Speed is given by the slope of the displacement - time graph. Steeper the slope, higher the speed.

Step2: Analyze each interval

For 1 h to 2 h: Slope is positive and moderate.
For 2 h to 3 h: Slope is positive and less steep than some others.
For 3 h to 4 h: Slope is positive and relatively less steep.
For 4 h to 5 h: Slope is negative and very steep. Magnitude of slope (speed) is highest in this interval.

Answer:

4 h to 5 h