Question

A block of mass $2\,kg$ rests on a horizontal surface. If a horizontal force of $5\,N$ is applied on the block the frictional force on, it is $(\mu _{k}=0.4,\,\mu _{s}=0.5)$

• A. $5\,\,N$
• B. $10\,\,N$
• C. $8\,\,N$
• D. zero

Answer 1

Answer: (C)

$8\,\,N$

Answer 2

The frictional force $F$ is given by
$F=\mu _{k}mg$
Given, $\mu_{k}=0.4,$
$m=2\,kg$,
$g=10 \, m/s^{2}$
$\therefore$ $F=0.4\times 2\times 10$
$F=8\,N$