0
$\begingroup$

So I was trying to figure out how the total angular momentum for the collection of particles is derived. Here in Wikipedia https://en.wikipedia.org/wiki/Angular_momentum#Center_of_mass is the derivation, but there is this one part that I do not understand. How does the term

$$ \sum_ir_i\times m_iV $$

vanish? I also know that $\sum_i m_ir_i=0$, but how does that help making the term vanish?

$\endgroup$
1
1
$\begingroup$

Rearrange the above equation as $\sum_i m_ir_i \times V$. Notice that this is the same as $m_i$ is a scalar. Now, $V$ is a constant vector in the above equation. We know that $\sum_i m_ir_i$ is $0$. So multiplying both sides by a constant vector is also $0$.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.