3. m=0.3kg
vo=10m/s
Em=?
Em=Ep+Ec
Ec=0.3*10^2/2
Ec=30/2=15J
Ep=mgh/3
Ep=0.3*10*h/3
h=?
"Folosimul ecuatia lui galilei":
V^2=vo^2+2gh
h=vo^2/2g=100:20=50m
Ep=3*h/3=50J
Em=50J+15J=65J
4.m=100kg
v1=3.6km/h=1m/s
v2=7.2km/h=2m/s
Lm=?
Em=?
DeltaV=v2-v1=1
Ec=Ep+Ec
Ec=100/2=50J
Ep=0
Em=50J
Lm=?
"Aici folosim teorema variatiei energiei mecanice":
Lm=DeltaEc
Lm=50J
