Density altitude is pressure altitude corrected for temperature.

Pressure altitude is the indicated altitude when an altimeter is set to 29.92 (1,013.2 mb).

Swept wings are designed to be the most effective at high speeds. At low speeds, a swept wing produces less lift than its straight counterpart.

An IRS is an Inertial Reference System  which consists of accelerometers, gyroscopes (laser) and a position computer.

The computer calculates the aircrafts position by direction and velocity sensed by the accelerometers from the initial latitude and longitude input.

An IRS enables the aircraft to fly great circle tracks and to navigate accurately across vast expanses where no ground based navigation aids are available.

Swept wings, thin wings.

Minimum Safe Altitude.

From West to East

East to West (In Africa during the summer)

Windshear is a change of wind speed and/or direction from place to place, including updraughts and down draughts.

It is ussualy characterized by a strong change over a short distance. Windshear can effect the flight path and airspeed and can be hazardous.

Yes.

There are permanent jet streams in the...

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.

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.