Question

the graph of an object’s position over time is a horizontal line and y is not equal to 0. what must be true about the object’s motion? (1 point)
○ the acceleration is negative.
○ the acceleration is constant and non-zero.
○ the velocity is zero.
○ the velocity is constant and non-zero.

Explanation:

In a position - time graph, the slope of the graph represents the velocity of the object. A horizontal line has a slope of 0. So, if the position - time graph is a horizontal line, the velocity (which is the rate of change of position with respect to time, given by the slope of the position - time graph) is 0.

• For the first option, acceleration being negative means the velocity is decreasing, but here velocity is 0 (constant), so this is incorrect.
• For the second option, if acceleration is constant and non - zero, the velocity would be changing (either increasing or decreasing), but the slope of the position - time graph is zero (velocity is constant at 0), so this is incorrect.
• For the fourth option, if velocity is constant and non - zero, the slope of the position - time graph would be a non - zero constant (a straight line with non - zero slope), but we have a horizontal line (slope = 0), so this is incorrect.

Answer:

The velocity is zero.