Question

1. which line on the graph shows an increase in speed? a b c d

Explanation:

Step1: Recall the relationship between speed and distance - time graph

Speed is the slope of the distance - time graph ($v=\frac{\Delta d}{\Delta t}$). An increasing speed means the slope of the graph is increasing.

Step2: Analyze each line

• Line A: The slope is decreasing (the curve is getting less steep as time increases), so speed is decreasing.
• Line B: The slope is constant (straight - line graph), so speed is constant.
• Line C: The slope is increasing (the curve is getting steeper as time increases), so speed is increasing.
• Line D: The slope is decreasing (the curve is approaching a horizontal line, and $\frac{\Delta d}{\Delta t}\to0$ as time increases), so speed is decreasing.

Answer:

C