The Solution:
We are required to find the force.
[tex]\begin{gathered} F\propto a \\ \text{This implies that:} \\ F=ka \end{gathered}[/tex]In this case,
F= force=30 N
a = acceleration = 3m/s
k = constant of proportionality = ?
We shall find the constant k by substituting the above values in the formula.
[tex]\begin{gathered} F=ka \\ 30=k(10) \end{gathered}[/tex]Dividing both sides by 10, we get
[tex]k=\frac{30}{10}=3[/tex]So,
The formula for finding Force is:
[tex]F=3a[/tex]To find the Force when a = 3m/s, we shall substitute 3 for a in the formula.
[tex]F=3\times3=9N[/tex]Therefore, the correct answer is 9 N