Problem 2
A rod of length ℓ moves at speed v perpendicular to itself and uniform field B, closing a circuit through R. Neglect rod resistance. Find emf, current, and magnetic drag. Use the stated ideal model: quantities are constant or vary only as specified, with no extra drag, losses, or external influences. State a sign convention, keep units consistent, and use a classical approximation only where appropriate. (a) Set up the governing equation from a fundamental law. (b) Solve for the requested quantity under the stated conditions. (c) Check the result using a suitable limit, sign, or unit test, and report both the expression and its physical meaning.
problems.proof.stepOf
problems.proof.analysis
Substitute the intermediate result into the expression for the requested observable. Keeping parameters symbolic until this step makes dependencies clear and avoids premature rounding.