Final answer:
Using Ampere's law, the average force per meter between two parallel wires in an AC appliance cord can be calculated. For a cord carrying 5.00 A and with wires 3.00 mm apart, the force is attractive. Special design features to compensate for this force are usually unnecessary due to its minimal magnitude.
Step-by-step explanation:
Magnetic Force between Two Parallel Conductors
When two parallel wires carry current, they exert a magnetic force on each other. This is described by the ampere's law which relates the force per unit length between two parallel conductors to the currents flowing through them and the distance separating them. Using the formula F/L = (μ0 * I1 * I2) / (2π * d), where μ0 is the vacuum permeability (μ0 = 4π x 10⁻⁷ T·m/A), I1 and I2 are the currents through the conductors, and d the distance between them, we can calculate the average force.
In the case of an AC appliance cord, with wires separated by 3.00 mm and carrying a 5.00-A current, the currents are flowing in opposite directions (one flowing into the appliance through the hot wire and the other flowing out through the neutral wire). Thus, we expect the force to be attractive. Using the ampere's law, we can find that the average force per meter, Favg/L.
To calculate the maximum force per meter, Fmax/L, we would consider the instants when the AC current reaches its peak value, which is √2 times the RMS value given for I. As for the nature of forces, since currents are in opposite directions, the force will be attractive. Special design features in appliance cords are generally not needed to compensate for this force, as it is typically very small.