Isaac is a Department for Education project at the University of Cambridge that develops understanding and confidence through problem solving in the physical sciences, by combining accessible and concise print resources with a state of the art online study tool. This book is a co-publication between Periphyseos Press/Isaac and Cambridge University Press. ESSENTIAL GCSE PHYSICS helps you master the concepts of physics in senior-school level courses (including GCSE, IGCSE and the US High School Diploma). Use the exercises to practise applying fundamental principles of physics to a range of situations, beginning with manipulating the essential equations. Notes, examples and guidance are given and the origins of all formulae are clearly explained. All problems can be answered on the Isaac online platform. Registration is free and gives both students and teachers personalised support through a sophisticated online marking system for all problems and a section-by-section archive of video lessons.