A certain vibrating system satisfies the equation u'' + γu' + u = 0. Find the value of the damping coefficient γ for which the quasi period of the damped motion is 40% greater than the period of the corresponding undamped motion.

Respuesta :

Answer:

Step-by-step explanation:

Using the formula for the ratio of period of  damped motion to the period of undamped motion

[tex]\frac{Td}{T} = (1 - \frac{γ^{2} }{4km} )^{-1/2}[/tex]

[tex]\frac{140}{100} = (1 - \frac{γ^{2} }{4} ) ^{-1/2}[/tex]

[tex]\frac{7}{5} = (1 - \frac{γ^{2} }{4} ) ^{-1/2}[/tex]

Solving for damping coefficient γ,

[tex](\frac{5}{7})^{2} = 1 - \frac{γ^{2} }{4}[/tex]

[tex]0.5102 = 1 - \frac{γ^{2} }{4}[/tex]

[tex]γ^{2} = (1 - 0.5102) *4 \\[/tex]

γ = [tex]\sqrt{1.9592}[/tex] = 1.4