Decision altitude (precision), the altitude at which a decision must be made during an ILS, MLS, or PAR instrument approach to either continue the approach or to execute a missed approach.

Forward motion forces air into the intake which is a convergent duct where it is compressed (causing a temperature rise).

Fuel is added and combustion takes place increasing the volume. The expanding gasses accelerate to the atmosphere through the exhaust duct nozzle producing a propulsive jet.

Mach number describes the speed of sound, which changes with the density of the medium it is travelling through.

When you reach the speed of sound, the compressibility effect creates a supersonic flow along the wing if you exceed a certain mach number.

This causes airflow separation and flutter.

It is therefore much safer and much easier to use a Mach number to express a limit at which compressibility effects start to tear the aircraft apart, as it is a constant value at all altitudes.

Because of the distance which has to be covered to reach 41.000 feet which may not be convenient for a short flight.

On long flights it is more typical to fly at 41.000 feet when the aircraft weight and performance allows.

Yes, for safety you will need a V2 speed.

Basic Empty Mass (BEM) is the mass of the aircraft with the basic equipment, unconsumable fluids and unusable fuel and oil.

GPWS is a central computer system that receives various data inputs on configuration, (radio altimeter) height/altitude and instrument landing system glide slope deviation and is able to alert the pilot when a dangerous situation is about to occur.

A Mach trimmer is a system that artificially corrects for Mach tuck.

Mach number

An anti-servo tab works in the opposite way to a servo tab.

It deploys in the same direction as the control surface, making the movement of the control surface more difficult and requires more force applied to the controls by the pilot.