Determine the node voltages $v_1$ and $v_2$ for the given circuit: 
To determine the node voltages \( V_1 \) and \( V_2 \), we can use the nodal analysis method. Let's apply Kirchhoff's current law (KCL) at nodes \( V_1 \) and \( V_2 \).

Step 1: Apply KCL at Node \( V_1 \)
Consider the current entering and leaving the node:
\[ 2 = \frac{V_1}{7} + \frac{V_1 - V_2}{15} + \frac{V_1}{3} \]Multiply through by 105 (LCM of 7, 15, and 3) to clear fractions:
\[ 210 = 15V_1 + 7(V_1 - V_2) + 35V_1 \]Simplify:
\[ 210 = 15V_1 + 7V_1 - 7V_2 + 35V_1 \]Combine like terms:
\[ 210 = 57V_1 - 7V_2 \]Step 2: Apply KCL at Node \( V_2 \)
Consider the current entering and leaving the node:
\[ \frac{V_2 - V_1}{15} + \frac{V_2}{5} = 4 \]Multiply through by 15 (LCM of 15 and 5) to clear fractions:
\[ V_2 - V_1 + 3V_2 = 60 \]Simplify:
\[ 4V_2 - V_1 = 60 \]Step 3: Solve the System of Equations
We now have two equations:
\[ 57V_1 - 7V_2 = 210 \] \[ 4V_2 - V_1 = 60 \]Rearrange the second equation:
\[ V_1 = 4V_2 - 60 \]Substitute \( V_1 \) in the first equation:
\[ 57(4V_2 - 60) - 7V_2 = 210 \]Expand and simplify:
\[ 228V_2 - 3420 - 7V_2 = 210 \] \[ 221V_2 = 3630 \]Solve for \( V_2 \):
\[ V_2 = 20 \, V \]Substitute \( V_2 \) back to find \( V_1 \):
\[ V_1 = 4 \times 20 - 60 = 80 - 60 = 20 \, V \]Thus, the node voltages are \( V_1 = 20 \, V \) and \( V_2 = 20 \, V \).
Conclusion: The correct answer is \( V_1 = 20 \, V \), \( V_2 = 20 \, V \).
Morgenthau's principles of political realism are:
A. Politics is rooted in permanent and unchanging human nature which is basically self centred, self-regarding and self-interested
B. Politics is an autonomous sphere of action and cannot therefore be reduced to morals
C. International Politics is an arena of conflicting self-interests
D. The ethics of international relations is situational ethics which is very different from private morality
Choose the correct answer from the options given below:
Who among the following political thinkers consider the anarchical self help system to be a compelling factor for States to maximise their relative power positions?