Taking off from Sydney, with a lot of cargo beside normal full load of passengers , mainly chilled meat and fruits from Australia. Maximum weight for take off for the Airbus A340 is 380,000 kg, 380 tons for short. This is how the take off speed calculated, using the LPCNG or the Less Paper Cockpit Next generation. The application is installed in each one of the pilots' laptop.
Start with the ops status, with the aircraft type, registration, the flight number and the route pairing. SYD to AUH in this case.
Next, the environmental data is input, such as the runway in use, 16R for take off in Sydney at that time, the wind, temperature,runway condition and the take off weight.
And, the computer computed the take off data such as the speeds, take off run, flap configuration, ASDA and etc..
The pilot will 'rotate' i e start to pitch the nose up for lift off at 170 knot, or 315 km/h.. and the take off run is 3.8 km . Runway length is 3.96 km only... very small room for error.
V1 : the speed beyond which if one engine failed, the take off should be continued because the runway length available is not sufficient to bring the plane to a complete stop.
VR : rotation speed, as explained above.
V2 : safety speed. The speed at which the plane will be fully controllable even if one engine fail and can climb safely.