第二句是病句。

if one don't come across his goal as a result , to comfort his mood you might tell him :"那是因为你没有准备(好well)" “那是因为你没有准备的”is ircorrect way to express your mean~you can say " 因为 那是你没有准备的(part)” it's OK~

the are same,but the first one is better.You can say like this 那是因为你没有准备的原因.This is better than那是因为你没有准备的.

May be the second one isn't end or they are same

the second one is incorrect