Resistor type elements are often used in electrical circuits. Consider the typical resis...

Resistor type elements are often used in electrical circuits. Consider the typical resistor element shown in Figure P2–23 with nodes 1 and 2. One form of Ohm’s law says that the potential voltage difference across two points is equal to the current I through the conductor times the resistance R between the two points. In equation form, V = IR where I denotes the current in units of amperes (amps) and V is the potential or voltage drop in units of volts (V) across the conductor of resistance R in units of ohms (Ω). Use the method in Section 2.2 to derive the ‘‘stiffness’’ matrix relating potential drop to current at the nodes shown as