Ground circuit and kirchhoff law(holiday 27.30)

[skyhj105]

Homework Statement

I attatched my question as a picture

Homework Equations

The Attempt at a Solution

1.i found a solution using kirchhoff law, V1=-11V,V2=-9V
and it was correct. but i`m not sure that my method was right.
i know that kirchhoff law is originated from charge and energy conservation but in the problem there is a circuit which is grounded, so i think that charge can in and out through it. consequently, charge doesn`t have to conserve in circuit.
can i use kirchhoff law in this problem? and why?2.i found that current go to ground is 0 using kirchhoff law. but i don`t know why it is

[/B]

 

[Hamal_Arietis]

If you see the ground and electrical circuit is an isolation system. V at ground =0. On the other hand, the ground doesn't create works.