Question

A machine part consist of two homogeneous solid cylinders coaxially. Then find the distance of center of mass from O.

• A. $\frac{17}{2}mm$
• B. $\frac{52}{7}mm$
• C. $\frac{15}{17}mm$
• D. $\frac{12}{7}mm$

Answer 1

The correct option is A $\frac{17}{2}mm$

Part is homogeneous. So, we can apply geometrical method for two dimension area.

Area of ABCD, $A_1=12\times 4=48m{m}^2$

Area of BEDF, $A_2=8\times 2=16m{m}^2$

$x_{com}=\frac{A_1\times 6+A_2\times 16}{A_1+A_2}=\frac{48\times 6+16\times 16}{48+16}=\frac{17}{2}$

Hence, center of mass from O is $\frac{17}{2}mm$