Question

read the passage and answer the following question(s).
passage 6449
directions: use the graphs below, which describe the motions of cars on a straight road, to answer any questions that follow.

question 6.
d. graph d

question 7.
which graph represents a car that is moving at constant speed?
a. graph a
b. graph b
c. graph c
d. graph d

Explanation:

To determine which graph represents a car moving at constant speed, we analyze each graph:

• Graph A: Speed vs. Time graph with a decreasing line, so speed is changing (decelerating).
• Graph B: Distance vs. Time graph with a horizontal line, meaning distance is constant (car is stationary).
• Graph C: Speed vs. Time graph with an increasing line, so speed is changing (accelerating).
• Graph D: Distance vs. Time graph with a straight - line (linear) positive slope. The formula for speed is $v=\frac{d}{t}$, and for a linear distance - time graph ($d = vt$ where $v$ is constant), the slope represents speed. A constant slope means constant speed.

Answer:

D. Graph D