Browse Questions

# Three particles of masses 8 kg, 4 kg and 4 kg situated at $(4,1),(-2,2)$ and $(1,-3)m$ are acted upon by external forces $6 \hat {j},-6 \hat {i}$ and $14 \hat {i}\;N$ respectively . The acceleration of the center of Mass of the system is

$\begin {array} {1 1} (a)\;0.625\;ms^{-2} & \quad (b)\;6.25\;ms^{-2} \\ (c)\;2.2 ms^{-2} & \quad (d)\;22\;ms^{-2} \end {array}$

$\bar {a}_{cm}=\large\frac{m_1 \bar {a}_1+m_2 \bar {a}_2+m_3\bar {a}_3}{m_1+m_2+m_3}$
$\qquad= \large\frac{8(\frac{6 \hat {j}}{8})+4(\frac{-6 \hat {i}}{4})+4 (\frac{14 \hat {i}}{4})}{16}$
$\qquad= 0.625ms^{-2}$
edited Jun 16, 2014