Question

Find the accelerations $a_1,a_2,a_3$ of the three blocks shown in figure $(6-E8)$ if a horizontal force of $10N$ is applied on $\left(a\right)2kg$ block, $\left(b\right)3kg$ block, $\left(c\right)7kg$ block. Take $g=10m/s^2$.
Take $g=10m/s^2$.

Answer 1

frictional force between 2 and 3kg is ${\mu }_1\times 20=4N$

frictional force between 3 and 7kg is ${\mu }_2\times 50=15N$

when 10N is applied on 2kg block

$10-4=2a_1=6$

$a_1=3m/s^2$

as limiting friction is greater for 3kg block, it does not move

$a_2=0$

$a_3=0$

when 10N is applied on 3kg block

as limiting friction is greater for 3kg block, it does not move

$a_1=0$

$a_2=0$

$a_3=0$

when 10N is applied on 7kg block

$10=7a_3$

$a_3=1.43m/s^2$

$a_2=1.43m/s^2$

$10-4=2a_1=6$

$a_1=3m/s^2$