Suggestion
For this problem, it is suggested that you place your observer on the rotating bar (exactly where on the bar is not really important, just that this observer rotates the same way as the bar). With this choice:
* omega is the angular velocity vector of the bar
* the velocity of the block relative to the observer is u_dot*j, regardless of where the observer stands on the bar
* the acceleration of the block relative to the observer is u_dot_dot*j, regardless of where the observer stands on the bar
NOTE:
As pointed out by the comment of john zuidema, I have a couple typos in the above post. In particular, the last two bullet points should read:
- the velocity of the block relative to the observer is u*j ...
- the acceleration of the block relative to the observer is u_dot*j ...
Apologies for the mistake.
4 comments:
isnt the velocity u? or did you mean u dot j to be read as u vector dotted into j vector, not time derivative of u vector? thanks for the help
Ooops ... you are correct; I meant to type u*j rather than u_dot*j.
Also, the acceleration as seen by the observer is u_dot*j (and not u_dot_dot*j).
Thanks for pointing out the typo!
On this problem, are they just looking for an equation with variables for the answer? what does it mean by interpret your result?
--to jonbrueck--
Yes, we are looking for a symbolic answer since numerical values have not been given for u, ud_dot, L, d and omega.
I think what the author is looking for here is for you to state, in words, the direction of the Coriolis component of acceleration in relation to the bar.
Later on in the course when we deal with kinetics (relationship between forces and motion) the Coriolis component of acceleration will produce a component of the normal force acting on the block by the rotating bar. Your Coriolis component of acceleration should be normal (perpendicular) to the bar.
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