contestada

Un reloj de péndulo de largo L y período T, aumenta su largo en ΔL (ΔL << L). Demuestre que su período aumenta en: ΔT = π ΔL /√(L g)

Respuesta :

Answer:

 ΔT = [tex]\pi \ \frac{\Delta L}{\sqrt{Lg} }[/tex]

Explanation:

In a simple harmonic motion, specifically in the simple pendulum, the angular velocity

          w = [tex]\sqrt{\frac{g}{L} }[/tex]

angular velocity and period are related

          w = 2π / T

we substitute

          2π / T = \sqrt{\frac{g}{L} }

          T = [tex]2\pi \ \sqrt{\frac{L}{g} }[/tex]

In this exercise indicate that for a long Lo the period is To, then and increase the long

          L = L₀ + ΔL

we substitute

           T = [tex]2\pi \ \sqrt{\frac{L + \Delta L}{g} }[/tex]

            T = [tex]2\pi \ \sqrt{\frac{L}{g} } \ \sqrt{1+ \frac{\Delta L}{L} }[/tex]

in general the length increments are small ΔL/L «1, let's use a series expansion

           [tex]\sqrt{1+ \ \frac{\Delta L}{L} } = 1 + \frac{1}{2} \frac{\Delta L}{L} + ...[/tex]  

we keep the linear term, let's substitute

           T = [tex]2\pi \ \sqrt{\frac{L}{g} } \ ( 1 + \frac{1}{2} \frac{\Delta L}{L} )[/tex]  

if we do

           T = T₀ + ΔT

           

           T₀ + ΔT = [tex]2\pi \sqrt{\frac{\Delta L}{g} } + \pi \ \sqrt{\frac{L}{g} } \ \frac{\Delta L}{L}[/tex]

            T₀ + ΔT = T₀ + [tex]\pi \sqrt{\frac{1}{Lg} } \ \Delta L[/tex]

            ΔT = [tex]\pi \ \frac{\Delta L}{\sqrt{Lg} }[/tex]