Răspuns:
m=650g=0.65kg
v0=36km/h=10m/s;
a). Ec lansare=m*v0^2/2
=0.65*100/2
=32.5J
b).EtA=EtB
Ec lansare=Ep maxima
32.5=m*g*h
h=Ec lansare/(m*g)
h=5m;
c)Lg=EpB=Ec lansare=32.5J
d)v1=v0/2=5m/s
EtC=EtA
m*v1^2/2+m*g*h1=32.5J
m(v1^2/2+g*h1)=32.5
g*h1=EcA/m -v1^2/2
h1=3.75m
Explicație: