Concrete is the most common artificial composite material of all and typically consists of loose stones (aggregate) held with a matrix of cement. Concrete is a very robust material, much more robust than cement, and will not compress or shatter even under quite a large compressive force.
2) Y-axis contains absolute brightness Why do astronomers use the H-R Diagram? Astronomers use H-R Diagrams to classify stars and to understand how stars change over time.
We take absolute value because distance is positive.) The point (x, y) represents any point on the curve. The distance d from any point (x, y) to the focus `(0, p)` is the same as the distance from (x, y) to the directrix. The axis of symmetry of this parabola is the y-axis. The Formula for a Parabola - Vertical Axis