Question

Two objects are moving along separate linear paths where each path is described by position, d, and time, t. The variable d is measured in meters, and the variable t is measured in seconds. The equation describing the graph of the position of the first object with respect to time is d = 2.5t + 2.2. The graph of the position of the second object is a parallel line passing through (t = 0, d = 1). What is the equation of the second graph?

Answer Choices:

d = 2.5t + 1



d = t + 2.5



d = -0.4t + 1



d = 2.5t + 3.2

Answer 1

The expression for the first line is

d = 2.5t + 2.2

Since the second line is parallel to the first line at (0, 1), the slope of the first line is equal to the second line.

From the general form f(x) = mc + b where m is the slope, the slope of the given equation is

m = 2.5

Since it passes to d = 1 at t = 0, the equation of the line is

(d – 1) = 2.5 (t – 0)

d = 2.5t +1

therefore the answer is A.