Question

From the fixed pulley, masses $2\, kg , 1 kg$ and $3\, kg$ are suspended as shown in the figure. Find the extension (in $m$ ) in the spring if spring constant $k=100 \,N / m$.
(Neglect oscillations due to spring)

Answer 1

For $3\, kg$ mass,
$3\, g-k x=3 a\,\,\,...(i)$
For $1 \, kg$ mạss,
$k x+g-T=a\,\,\,...(ii)$
For $2\, kg$ mass,
$T-2 g=2 a\,\,\,...(iii)$
Adding (i), (ii) and (iii),
we get $a=(g / 3)$
Hence, $x=0.20\, m$