Step 1: Express velocity as function of position.
From graph, velocity decreases linearly with position:
\[
v = -mx + c
\]
Step 2: Relation between acceleration and velocity.
\[
a = v \dfrac{dv}{dx}
\]
Step 3: Differentiating velocity.
\[
\dfrac{dv}{dx} = -m
\]
Step 4: Expression for acceleration.
\[
a = (-mx + c)(-m) = m^2 x - mc
\]
Thus, acceleration varies linearly with position with positive slope.