To derive the equation for Simple Harmonic Motion (SHM), start by establishing the relationship between acceleration and displacement, noting that acceleration is directly proportional to the negative of displacement. Using Newton's second law (F=ma), express acceleration (a) in terms of displacement (x), leading to the equation a = -ω²x, where ω is the angular frequency. The angular frequency can be related to the period (T) by the formula ω = 2π/T, which can be rearranged to T = 2π/ω. This derivation connects mass (m) and spring constant (k) to the period of oscillation, resulting in T = 2π√(m/k). Understanding these relationships is crucial for modeling harmonic motion effectively.