timpul 0-3 a=v/t=3/3=1m/s
timpul 6-8 a=v/t=(20-3)/(8-6) = 17/2=8,8 m/s
timpul 10-20 . a=v/t= (-20)/(20-10)= -20/10= -2m/s (este deceleratie, caci viteza scade)
