Question

Force acting on a block versus time and acceleration versus time graph are as shown in nfigure. Taking value of $g=10m{s}^{-2}$, match the following two columns.

Answer 1

A $2Kg$ block has normal reaction,
$N=20N$
It doesn't move till $t=4s$ i.e. $F=8N$
Thus static coefficient,
${\mu }_1=8÷20=0.4$
The block gets an acceleration of $1m{s}^{-2}$ when a force of 8N acts on it.

Thus, the force of friction is $8-2=6N$

Thus kinetic coefficient, ${\mu }_2=6÷20=0.3$
at $t=0.1s$
Force of friction is same as force applied $=0.2N$
At $t=8s$
net force on block,
$F_{net}=16-6=10N$
Thus acceleration, $a=10÷2=5$
Thus, $a÷10=0.5$