Digital PSAT Math Practice Question 296: Answer and Explanation

Question: 296

Acceleration is calculated by taking the change in velocity between two points and dividing it by the change in distance between those same two points. Suppose that a scientist graphs a line of the constant acceleration of a car on the xy-coordinate plane, using distance as the x-coordinates and velocity as the y-coordinates. If this line intersects the y-axis at point b, what property of the line corresponds to the car's acceleration?

• A. Its y-intercept
• B. Its slope
• C. Its y-values (range)
• D. Its x-values (domain)

Correct Answer: B

Explanation:

(B) You are told that acceleration is equal to between two points. Note that to find the slope of any line, you take . Now, the scientist graphs the line with distance as the x coordinates and velocity as the y coordinates. So, in your case, change in y corresponds to change in velocity, while change in x corresponds to change in distance. Thus, the slope of your line equals , which is the formula for acceleration. Thus, the answer is choice (B).