Looking for Challenging Physics Exercises? Any Recommendations?

[fisico]

Hello everyone!

My question is simple. Is there some website with really good and tricky physics exercises? I'm in 12th grade but I have also been studying and practicing by myself for some time now. I need 12th grade topics but with harder level questions. Any ideas would be great...

Thanks a lot.

 

[durt]

You can do some past IPhO problems: http://www.jyu.fi/tdk/kastdk/olympiads/" .

 

[fisico]

But hey, I meant hard but not that hard. Can you lower the bar a little bit more? Also, any good books with the types of problems discribed that are mentioned would be appreciated. Thanks.