A force $F$ whose modulus varies (shown in the figure from below) is applied to a block of $5\,kg$ of mass. This block slides over a flat rugous surface which has friction coefficients $\mu_s=0.3$ and $\mu_k=0.2$ respectively. It is known that the block begins moving from rest. Find approximately the speed in $\frac{m}{s}$ of the block when $t=5\,s$. You may use the value of the gravity $g=9.81\,\frac{m}{s^2}$.

The alternatives given in my book are as follows:

$\begin{array}{ll}

1.&1.54\,\frac{m}{s}\\

2.&2.19\,\frac{m}{s}\\

3.&3.22\,\frac{m}{s}\\

4.&4.16\,\frac{m}{s}\\

5.&5.24\,\frac{m}{s}\\

\end{array}$

I'm here lost at exactly how should I relate the graph given to get the necessary information in order to get the speed. The source of my confusion is that how exactly should I understand the word approximately speed?. Could it be that it is referred this way because is related with the average net force?.

Can somebody help me here please?.