Question

Three point masses $1.0kg$ , $1.5kg$ and $2.5kg$ are placed at the vertices of a right-angle triangle of sides $4.0cm$ , $3.0cm$ and $5.0cm$ , as shown in the figure. The centre of mass of the system is

• A. $0.6cm$ right and $2.0cm$ above $1kg$ mass
• B. $2.0cm$ right and $0.9cm$ above $1kg$ mass
• C. $0.9cm$ right and $2.0cm$ above $1kg$ mass
• D. $1.5cm$ right and $1.2cm$ above $1kg$ mass

Answer 1

Answer: (C)

Let us assume that the origin of the coordinate system is at the location of $1kg$ mass, then

$x_{cm}=\frac{1 \times 0 + 1 . 5 \times 3 + 2 . 5 \times 0}{5}=0.9cm$
$y_{cm}=\frac{1 \times 0 + 1 . 5 \times 0 + 2 . 5 \times 4}{5}=2cm$