Question #43039

This question tests the synthesis of non-inertial frame dynamics with electrodynamic instrumentation.

The primary trap is the assumption that a galvanometer's full-scale deflection current ($I_g$) is an invariant electrical property.

Students often misapply the shunt formula by keeping $I_g$ constant, ignoring that the mechanical restoring torque—and thus the required magnetic deflecting torque—depends on the effective gravity ($g_{\text{eff}}$) in the accelerating frame.

By using a gravity-based restoring mechanism, the problem forces the realization that $I_g \propto g_{\text{eff}}$.

Secondary traps involve incorrectly scaling the shunt resistance linearly with $g_{\text{eff}}$ (yielding $4.0 \ \Omega$) or approximating the shunt formula by ignoring the galvanometer current in the denominator (yielding $3.6 \ \Omega$).