The lectures will cover material from the reading assignments. Some portion of the reading assignments may not be covered in lecture in order to allow time to emphasize other areas and present demonstrations that illustrate the physical principles covered. (i.e you are expected to come to class having read your assigment!)
A traditional rule of thumb in college is that you should study at least two hours outside of class for every hour spent in class. The text and the course are designed with that expectation. That, of course, is an average. Some chapters are straightforward and will go quickly, but others will likely require much more than two study hours per class. Individual variations in ability and motivation will also play a role in how much study time you need. (you need to read the textbook in order to solve the hw problems!)