The problem is as follows:

The alternatives given in my book are:

$\begin{array}{ll}

1.&58\,N\\

2.&42\,N\\

3.&30\,N\\

4.&25\,N\\

5.&10\,N\\

\end{array}$

In my attempt to solve this problem I thought that:

For the lighter block:

$F-mg\times \mu_{s}=0$

$F= 5\times 10 \left(0.45\right)=22.5\,N$

But this ain't the case. I don't know how to relate this with what is happening in the block from below. :help:

The answer supposedly is $30\,N$. But I have no idea how to get there. Can somebody offer some help here please?.

In the figure from below there are two blocks, one over another. The system is at rest. The horizontal surface is frictionless and the coefficient of static friction is $0.45$ Find the maximum value of $F$ in $N$ such as the blocks will not slide between them. (You may use $g=10\frac{m}{s^{2}}$)

The alternatives given in my book are:

$\begin{array}{ll}

1.&58\,N\\

2.&42\,N\\

3.&30\,N\\

4.&25\,N\\

5.&10\,N\\

\end{array}$

In my attempt to solve this problem I thought that:

For the lighter block:

$F-mg\times \mu_{s}=0$

$F= 5\times 10 \left(0.45\right)=22.5\,N$

But this ain't the case. I don't know how to relate this with what is happening in the block from below. :help:

The answer supposedly is $30\,N$. But I have no idea how to get there. Can somebody offer some help here please?.

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