Go to the AWS web site home page, click on Certification, and there is some info on the CWEng certification. There are 2 Adobe Acrobat documents available for viewing/download at the end of the article that have more info. One of them has a pretty extensive reading list to help you study for the exam and a breakdown of the areas covered on the exam. For your specific question, get a study guide for the EIT Exam at your local bookstore. It will review the basics for the math, physics, chemistry, strength of materials, fluid mechanics, heat, etc. areas of the exams.
Marty