Answer:
D) Acceleration is positive and increasing.
Explanation:
Acceleration is defined as the rate of change of velocity per unit time; in formulas:
[tex]a=\frac{\Delta v}{\Delta t}[/tex]
where [tex]\Delta v[/tex] is the variation of velocity and [tex]\Delta t[/tex] is the variation in time.
The graph shows the velocity vs the time of a moving object. We can see that [tex]\Delta v[/tex] is the increment on the y-axis, while [tex]\Delta t[/tex] is the increment on the x axis: therefore, the ratio [tex]\frac{\Delta v}{\Delta t}[/tex] is the slope of the curve. In fact, in a velocity-time graph, the slope of the curve corresponds to the acceleration of the object.
In this particular graph, we see that the slope of the curve continues to increase: therefore, the acceleration is positive (because the slope is positive, since the velocity is increasing) and increasing (because the slope is increasing).