15. how does the acceleration of a wheelbarrow change as the force applied to it increases?

Explanation:

Step1: Recall Newton's second law

$F = ma$, where $F$ is force, $m$ is mass and $a$ is acceleration.

Step2: Solve for acceleration

$a=\frac{F}{m}$.

Step3: Analyze the relationship

Mass $m$ of the wheel - barrow is constant. As $F$ increases, since $a=\frac{F}{m}$ and $m$ is fixed, $a$ increases.

Answer:

The acceleration of the wheel - barrow increases as the force applied to it increases.