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#sinusoidal function

2 public questions tagged with this topic.

Which function represents SHM? (\( \omega \) is a positive constant)

**Distinction between periodic and oscillatory** clarifies all SHM is periodic but not all periodic is SHM. SHM requires linear restoring force and inertia, a ∝ -x, with ω = √(k/m). Functions like sin²ωt have period π/ω but lack a = -ω² x, thus periodic not SHM, while uniform circular motion is periodic without linear oscillation. SHM requires a = -ω² x : (a) 5 cos (3ω t + (π/6)) : a = -5 (3ω)² cos (3ω t + (π/6)) = -ω² x , SHM. (b) sin ω t + cos 2ω t : Not SHM (mixed frequencies). e⁻ω t : Not periodic. (d) sin² ω

Ref: NCERT > Physics Book > Oscillations > Periodic Motion and SHM Basic Concepts

A stationary wave is given by \( y = 0.07 \sin (\frac{\pi x}{5}) \cos (90\pi t) \), where \( x \) and \( y \) are in met

**Wave equation** y(x,t) = A sin(kx - ωt + φ) describes displacement of progressive harmonic wave, where k = 2π/λ wave number (rad/m), ω = 2πf angular frequency (rad/s), v = ω/k wave speed (m/s). Sign of ωt indicates direction, amplitude A is maximum displacement. Form: y = A sin (kx) cos (ω t) , k = (π/5) rad/m . Wavelength: λ = (2π/k) = (2π/(π/5)) = 10 m . Distance between nodes: (λ/2) = (10/2) = 5 m . Using v = fλ and standing-wave condition fₙ = n v/(2L) or v/(4L) as applicable, calculation yields 5 m, illustrating frequency-length-speed interdependence and quantization by boundaries.

Ref: NCERT > Physics Book > Waves > Wave Equation and Displacement Relation