Paul Wilson gave the answer to IHL’s very thought provoking question.
Kinetic Energy = 0.5mass multiplied by velocity squared
Actually, it comes from Einstein's famous formula:
E = m x c squared
In simple terms for us pilots to have a useful tool for determining braking energy, we can consider only these two major variables.
1 Aircraft weight
2 Groundspeed at brake application
As a result you can see that you can vary the a/c weight by quite a lot and not make too much difference to the energy required. But because the speed factor is squared,
changes to brake application groundspeed becomes the most critical factor in determining brake energy required and how hot your brakes get.
For the Airbus A330/A340 series this information is available in a graph in the Minimum Equipment List for operation with unserviceable brake temperature indication. Other factors such as runway slope, number of reversers operating, etc,etc are allowed in this Airbus graph for but the major effects of weight and especially speed are very apparent.
Einstein right again? Buy that man a beer!
Centaurus,
I found some guidance at John Tullamarine’s:
Useful Website References (Tech Log ‘sticky’).
I have never been rated on the B737 and I don\'t know if the information is authoritive.
http://www.b737.org.uk/pilotnotes.htm
http://www.b737.org.uk/perf_brakecooling.gif