Earnings: Amgen, Inc., United States Steel Corporation, Western Digital, More (AMGN, X, WDC, More) January 27, 2015. After the bell on Tuesday, a number of big name, dividend paying companies announced their quarterly earnings. Below, we look at these earnings reports and break down the important points for investors.
As temperature increases, the density of liquids and gases decreases; as temperature decreases, the density increases. Density is the amount of mass per unit of volume.
Lift and drag depend linearly on the density of the fluid. Halving the density halves the lift, halving the density halves the drag. The fluid density depends on the type of fluid and the depth of the fluid. In the atmosphere, air density decreases as altitude increases. This explains why airplanes have a flight ceiling, an altitude above which it cannot fly. As an airplane ascends, a point is eventually reached where there just isn't enough air mass to generate enough lift to overcome the airplane's weight.