In simple harmonic motion (SHM), the total energy (E) is constant and given by E = PE + KE where, PE is potential energy and KE is kinetic energy.
At any displacement (x) from the equilibrium position:
PE = $\frac{1}{2}kx^2$
KE = $\frac{1}{2}k(A^2 - x^2)$
When PE = KE: $\frac{1}{2}kx^2 = \frac{1}{2}k(A^2 - x^2)$
$x^2 = A^2 - x^2$
$2x^2 = A^2$
$x = \frac{A}{\sqrt{2}}$
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is: