Question

Find the maximum force $F$ to be applied for the system shown, so that the two blocks move together. Take $g=10{\text{m/s}}^2$.

• A. $\text{20 N}$
• B. $\text{30 N}$
• C. $\text{25 N}$
• D. $\text{50 N}$

Answer 1

The correct option is C $\text{25 N}$

The values given in the question are,
${\mu }_1=0.2;{\mu }_2=0.3;m_1=4\text{kg};m_2=1\text{kg}$

We know that by formula,

$F_{max}=(m_1+m_2)({\mu }_{1}g+a_s)$ and also we know that $a_s={\mu }_{2}g$

$F_{max}=(4+1)(0.2\times 10+0.3\times 10)=25\text{N}$.

Hence the maximum force in this case is $\text{25 N}$.