Got Accepted. What now?

[IAmKenny]

I have been recently accepted into a graduate school for nuclear physics. After reading the departmental website, I believe my first-year classes will consist of core courses such as classical mechanics, E&M, and quantum. I will have a lot of free time during the upcoming summer, so I want to put those time to good use. My question is: is there a list of books that I should go through during the summer to give myself somewhat of a headstart? Is there something I should be doing besides reading ahead?

[fuzzylogician]

Ask your department if there is anything they recommend. Also strongly consider using this time to rest and recharge your batteries, because first year can be very hard. 

[TakeruK]

I'd second the advice to take the time to recharge before grad school.

But if you really want to do something over the summer, I think it's better to use this time for getting ahead on research instead of classes. When the semester begins, you'll find that classes expand to take up as much time as you will let it. The only way I was able to carve out time for research during my coursework years was to set a time limit on how much time to devote to classes and learn to submit imperfect homework. So, depending on how your program matches you up with thesis advisors, maybe talk to professors that you would be interested in working with instead. You might even be able to arrange for a summer RAship so you can start funded/paid work in the weeks/months before the term. I find that the first few weeks/months in a new project benefits the most from having a full 40 hour work week to devote to reading and new research. It's really hard (for me) to kick off a new project with only 10 hours a week because there are classes going on too.

This advice doesn't apply if your program doesn't have students begin research until the first summer or 2nd year. In addition, another exception may be if you come from a non-physics background or have some missing courses (or did poorly in some important areas as an undergrad) so you want to ensure you have the right foundations for the qualifying exam. 

[RichardSFord]

It's always better to start early so ,there are few books like Classical mechanics:System of particles and Hamiltonian Dynamics by Walter Greiner and Fundamental laws of mechanics by Igor Irodov that I would recommend you to go through.Beside this you can also go through the video tutorials and ppts if you want. Video tutorials will help  you  to understand the concepts and facts in a better way.