Question: Re-watching the 2009 movie for the first time after answering [this question about shield collisions](https://scifi.stackexchange.com/questions/9312/what-would-happen-in-the-star-trek-universe-if-shields-collided), I noticed the following:

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> *Enterprise* is about to drop out of warp in Vulcan space.
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> Captain Pike: Raise shields, red alert.
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> *Enterprise* drops out of warp, encounters the debris field of the other star fleet vessels and **suffers hull damage due to a low velocity graze against a piece of debris even though its shields are up and fully charged.**
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The shields are capable of pushing interstellar dust out of the way at high impulse (which is relativistic), *and* surviving photon torpedo detonations.

So what happened?

Answer: 
I think the shield technology is a little different than the later ellipsoid ones. It is an energy field applied to the hull that deflects energy weapons. In *Star Trek 6* you can see torpedoes hitting the hull even though the shields are up, but they cause little damage compared to later when the shields are down.
I don't believe there are canonical examples of starships plowing through fields of ship-sized debris and expecting the shields to handle it for them. Maybe this is just because captains prefer to preserve their shield power, but it's certainly plausible that shields just aren't meant to handle that sort of thing.