Question

A block of mass $10\text{kg}$ is at rest on a rough horizontal surface. A force of $40\text{N}$ is applied on it as shown in figure. The acceleration of the block is: (Take $g=10{\text{m/s}}^2$)

• A. $0{\text{m/s}}^2$
• B. $10{\text{m/s}}^2$
• C. $20{\text{m/s}}^2$
• D. $30{\text{m/s}}^2$

Answer 1

The correct option is A $0{\text{m/s}}^2$

From the FBD
$R=10g-40\sin {37}^{\circ }$
$=100-24=76\text{N}$
$\therefore (f_s{)}_{\text{max}}={\mu }_{s}R$
$=0.5\times 76=38\text{N}$
But applied horizontal force $=40\cos {37}^{\circ }=32\text{N}<(f_s{)}_{\text{max}}$.
Hence, the block does not move.