Question

What will be the acceleration of centre of mass (in $m/s^{2}$ ) of the system of two blocks as shown in figure $\left(g = 10 m / s^{2}\right)$ ?

• A. Zero
• B. $\frac{12 \hat{i} - 8 \hat{j}}{5}$
• C. $\frac{12 \hat{i} - 4 \hat{j}}{5}$
• D. $\frac{4 \hat{i} - 12 \hat{j}}{5}$

Answer 1

Answer: (B)

$a=\frac{2 g}{2 + 3}=4m/s^{2}$
$\left(\overset{ \rightarrow }{a}\right)_{CM}=\frac{m_{1} \left(\overset{ \rightarrow }{a}\right)_{1} + m_{2} \left(\overset{ \rightarrow }{a}\right)_{2}}{m_{1} + m_{2}}=\frac{3 \left(\right. 4 \hat{i} \left.\right) + 2 \left(\right. - 4 \hat{j} \left.\right)}{3 + 2}=\frac{12 \hat{i} - 8 \hat{j}}{5}$