- #1
KT KIM
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This is from text [Introduction to Lagrangian and Hamiltonian Mechanics] on NTNU opencourse.
Annnnd... I don't use english as my primary language, so sorry for poor sentences.
I can't get two things in here.
First, at (1.12) I can't understand how L dot derivated like that.
Since I know differentiation of cross product should be done like
d/dt(AxB)=d/dt(A) x B + A x d/dt(B)
then, at (1.12), why it doesn't have the terms of d/dt(r) x p ?
I think it only has the terms of r x d/dt(p)
Second, I can't get how
were derived by using (1.13), How could ri X Fji = 1/2(rij X Fji)
is possible?
These might be dumb questions, but please help me.