Dear prakhar ..
Yaar there is no need to use bhaiya .. i am also just a kid like u .. u can call me puneet .. :)
Well yaar there is really nothing much to worry about ..
Go steadily and u will be able to cover the entire syllabus ..
What i suggest is that u shud first sit and decide that this is what i have to do till JEE. I suggest that u shud only concentrate on the stuff that u had already done during the period of coaching ..
As u are correct , there is little time now and u will also have ur board exams in between ... so it is better that u aim little and achieve ... otherwise if u will keep ur expectations high ... thn it will breed tension ... rite ..
Now coming to the point that u are not able to attempt question u were able to solve in 11th ... well this does happens at times and is quite obvious .. it has been a long time u read those things .. take it easy .. read the theory once agian and then attpempt these questions ...
Now about ur physics .. if u believe that ur concepts are weak and u need to learn the theory .. thn u can go for Resnick .. however I always prefer H.C.Verma .. make ur mind bout that on ur own ..
Just go for the material u already have and which u have covered in ur phase of coaching ..
I hope it helps ....
cheers