Quirino Sugon Jr, PhD

This book is entitled "An Introduction to Physics An Introduction to Physics " and it is intended to be just that, a first course in basic physics as present-day scientists understand the field of physics. The intended reader is a student in the STEM strack of Senior High School who has already completed an equivalent of a year on physics in Junior High School. It sometimes happens that a student has been exposed to a course entitled "Physics" which was in reality, a mere description of household gadgets and the memorization of formulas. It is the feeling of the authors that such a student has not yet been "introduced to physics." For the general student, the primary aim in studying physics should be  formation  rather than  information . Much of the student's earlier education may have developed the  memory , storing it with useful or at least interesting bits of information. However, education should also develop the  intellect , teaching the stu

Vincent S. Cronin wrote A Primer on Focal Mechanism Solutions for Geologists (2010) . My interest in his work is in his descriptions of fault vectors and angles. I need to use these standard names if I wish to write a paper on Focal Mechanism of Earthquakes. Based on Cronin's diagram in p. 6, the reference strike, which we shall denote by $\mathbf e_{strike}$ appears to be the direction of the fault line as seen from a drone camera flying overhead high above the fault. The dip vector, which we shall denote by $\mathbf e_{dip}$, is a vector perpendicular to the reference strike $\mathbf e_{strike}$ and lies along the fault plane. The direction of $\mathbf e_{dip}$ is downward along the fault in Cronin. In this way, if we define the rake $\mathbf e_{rake}$ as the direction of the movement of the one side of the fault, then $\mathbf e_{rake}$ can be expressed as a rotation of $\mathbf e_{strike}$ about $\mathbf e_{dip}\times\mathbf e_{strike}$ by an angle $\theta_{rake}$, which is