Why can't I calculate torque about the rod's end in its own reference frame?

  • Level: Graduate 
  • Thread starter Thread starter Dweirdo
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
8 replies · 3K views
Dweirdo
Messages
174
Reaction score
0
Hi

if i have let's say a rod swinging on a pivot, and i calculate the moment of inertia around the axis, which is the pivot, and i get the angular acceleration.
now let's say i want to the the same around the other end of the rod, but the thing is that in the lab F.O.R it is moving around the pivot, although in the F.O.R of the other end of the rod, the pivot moves around that end, so why can't i make the same equations, and substitute angular acceleration with the one that i got before, and then find the net torque,
i mean, because it's an accelerated f.O.R i need to be careful, and add some factious forces and stuff, so how do i deal with that?
thanks
Dweirdo
 
Physics news on Phys.org

Discussion

Dweirdo said:
… why can't i make the same equations, and substitute angular acceleration with the one that i got before, and then find the net torque, i mean, because it's an accelerated f.O.R i need to be careful, and add some factious forces and stuff, so how do i deal with that?

Hi Dweirdo! :wink:

Yes, you can do that … see, for example, http://en.wikipedia.org/wiki/Fictitious_force :smile:
 
Hi Tim,and thanks
I've looked it p, but which one of these should i use in my case:
1)Rotating observer
2)Rotating coordinate systems

and what is this symbol:Ω?
thanks :)
Dweirdo
 
Dweirdo said:
… which one of these should i use in my case:
1)Rotating observer
2)Rotating coordinate systems

Theyr'e the same aren't they? :confused:

(and Ω is angular velocity)
 
idk they come up as 2 different sectors :P oh well
and why the hell they have to make things so complicated , omega should be angular velocitY! :P
thanks again,
dweirdo
 
Ω

Dweirdo said:
and why the hell they have to make things so complicated , omega should be angular velocitY! :P

Hi Dweirdo! :smile:

Ω is capital ω … see http://en.wikipedia.org/wiki/Greek_alphabet :wink:

(that's partly why someone with a sense of humour made Ω the symbol for ohm! :biggrin:)
 
haha cool :) still omega sounds way smoother :P
i still think they just try to make things complicated :)
*goes to study greek alphabet* :DD
Dweirdo