Deriving dA/dt = \omega x A: Proof for Constant Vector A and Vector \omega

[nna]

I hope somebody can help me.. this is the problem i have to proof that if A is a constant vector then I can write its derivate as dA/dt = \omega x A.. where \omega is a vector, and the "x" is the cross product

 

[tiny-tim]

Welcome to PF!

Hi nna! Welcome to PF!

(have an omega: ω )

I hope somebody can help me.. this is the problem i have to proof that if A is a constant vector then I can write its derivate as dA/dt = \omega x A.. where \omega is a vector, and the "x" is the cross product

(You mean "if A is constant in magnitude".)

Hint: if the magnitude is constant, then so is the magnitude squared, which is A.A.

 

[nna]

Sorry :( but I don't understand how that helps...

 

[tiny-tim]

Differentiate it …

what do you get? ​

 

[nna]

ok ok thank you so much! it really helps... jaja it was very easy sorry