Question

A block of mass $2kg$ is kept on a rough horizontal floor and pulled with a force $F$. If the coefficient of friction is $0.5$. then the minimum force required to move the block is:-

• A. $10N$
• B. $\frac{100}{11}N$
• C. $\frac{100}{8}N$
• D. $20N$

Answer 1

The correct option is B $\frac{100}{11}N$

$N=mg-F\sin {37}^{\circ }N=20-\frac{3F}{5}{f}_{max}=\mu N=0.5(20-\frac{3F}{5})=(10-\frac{3F}{10})$

It must be equal to $F\cos {37}^{\circ }$

$F\times \frac{4}{5}=10-\frac{3F}{10}\frac{11F}{10}=10F=\frac{100}{11}N$