A rod of length is $3 \mathrm{~m}$ and its mass acting per unit length is directly proportional to distance $x$ from one of its end, then its centre of gravity from that end will be at:

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Aicharya · Accepted Answer

Here $r=k x$ where $k=$ constant mass of small element of $d x$ length is $\begin{aligned} & d m=k x \cdot d x \ & \mathrm{X}_{\mathrm{CM}}=\frac{\int x d m}{\int d m}=\frac{\int_0^3 x(x d x)}{\int_0^3 x d x} \ &=\frac{\left[\frac{x^3}{3}ight]_0^3}{\left[\frac{x^2}{2}ight]_0^3}=\frac{\frac{27}{3}}{\frac{9}{2}}=2 \end{aligned}$

A rod of length is $3 \mathrm{~m}$ and its mass acting per unit length is directly proportional to distance…

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