r0 apa=ro1=1000kg/m³; ro ulei=ro2=800kg/m³; h1=h2=h; S1/S2=2
a)
p1=G1/S1=m1×g/S1=V1×ro1×g/S1=S1×h1×ro1×g/S1=h×ro1×g
p2=G2/S2=m2×g/S2=V2×ro2×g/S2=S2×h2×ro2×g/S2=h×ro2×g
p1/p2=h×ro1×g/(h×ro2×g)=ro1/ro2
p1/p2=1000/800=1,25.
b)
Fortele de presiune sunt tocma greutatile coloanelor de lichid.
Deci F1=G1 si F2=G2
F1=m1×g=V1×ro1×g=S1×h1×ro1×g
F2=m2×g=V2×ro2×g=S2×h2×ro2×g
CU h1=h2=h
F1/F2=S1×h×ro1×g/(S2×h×ro2×g)
Simplifcam cu h si cu g
F1/F2=(S1/S2)×(ro1/ro2)
Dar S1/S2=2
F1/F2=2×ro1/ro2
F1/F2=2×1000/800=2×1,25=2,5