对于一个有多个质点的系统, I = ∑ i = 1 N m i r i 2 {\displaystyle I=\sum _{i=1}^{N}{m_{i}r_{i}^{2}}} , , 的笛卡尔基e, e, e
I = {\displaystyle I={\begin{bmatrix}{\frac {2}{3}}mr^{2}&0&0\\0&{\frac {2}{3}}mr^{2}&0\\0&0&{\frac {2}{3}}mr^{2}\end{bmatrix}}}
I = {\displaystyle I={\begin{bmatrix}{\frac {1}{3}}ml^{2}&0&0\\0&0&0\\0&0&{\frac {1}{3}}ml^{2}\end{bmatrix}}}
I = {\displaystyle I={\begin{bmatrix}{\frac {1}{12}}ml^{2}&0&0\\0&0&0\\0&0&{\frac {1}{12}}ml^{2}\end{bmatrix}}}
I = {\displaystyle I={\begin{bmatrix}{\frac {1}{12}}m(3r^{2}+h^{2})&0&0\\0&{\frac {1}{12}}m(3r^{2}+h^{2})&0\\0&0&{\frac {1}{2}}mr^{2}\end{bmatrix}}}
I = {\displaystyle I={\begin{bmatrix}{\frac {1}{12}}m(3(r_{1}^{2}+r_{2}^{2})+h^{2})&0&0\\0&{\frac {1}{12}}m(3(r_{1}^{2}+r_{2}^{2})+h^{2})&0\\0&0&{\frac {1}{2}}m(r_{1}^{2}+r_{2}^{2})\end{bmatrix}}}