Ei - energia initiala
Ef - energi afinala
Ei=m*vi^2/2=850kg*(90*1000m/3600s)^2/2=850*25^/2=850*625/2=
=265625J
Ef=m*vf^2/2=850kg*(72*1000m/3600s)^2/2=850*20^/2=850*400/2=
=170000J
Variatia energiei cinetice este 265625-170000=95625J aceasta energie se transforma in caldura ca urmare a frecarilor care apar in sistemul de franare.