Question

A block of mass $0.8\text{kg}$ is placed on a rough horizontal floor having coefficient of kinetic friction, $\mu =0.2$. Find the acceleration (in ${\text{m/s}}^2$) of the block. Take $g=10{\text{m/s}}^2$

Answer 1

Weight of the block, $W=mg=0.8\times 10=8N$
FBD of the block,
From FBD,
$N=20\sin {53}^{\circ }+8=24$
$f=\mu N=0.2\times 24=4.8\text{N}$
And along the horizontal,
$a=\frac{F}{m}=\frac{20\cos {53}^{\circ }-f}{m}$
$⟹a=\frac{12-4.8}{0.8}=9{\text{m/s}}^2$