Question

The coordinates of centre of mass of a uniform flag shaped lamina (thin flat plate) of mass $4kg$. (The coordinates of the same are shown in figure) are :

• A. (1.2 5m, 1.50 m )
• B. (0.75 m, 0.75 m)
• C. (0.75 m, 1.75 m)
• D. (1 m, 1.75 m)

Answer 1

Answer: (C)

$m_1=3kg<br/>m_2=1kg$
Mass of plate-1 is assumed to be concentratedat $\left(0.5,1.5\right)$
Mass of plate-2 is assumed to be concentratedat $\left(1.5,2.5\right).$
$x_{cm}=\frac{m_1{x}_1+m_2{x}_2}{m_1+m_2}=\frac{3\times 0.5+1\times 1.5}{4}=0.75$
$y_{cm}=\frac{m_1{y}_1+m_2{y}_2}{m_1+m_2}=\frac{3\times 0.5+1\times 1.5}{4}=0.75$