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A surgical microscope weighing 200 lb is hung from a ceiling by four springs with stiffness 25 lb/ft. The ceiling has a vibration amplitude of 0.05mm at 2 Hz (a typical resonant frequency of a building). a) If there is no damping, how much transmitted vibration (amplitude of displacement) does the microscope experience

Respuesta :

Answer:

If there is no damping, the amount of transmitted vibration that the microscope experienced is   = [tex]5.676*10^{-3} \ mm[/tex]

Explanation:

The motion of the ceiling is y = Y sinωt

y = 0.05 sin (2 π × 2) t

y = 0.05 sin 4 π t

K = 25 lb/ft  × 4  sorings

K = 100 lb/ft

Amplitude of the microscope  [tex]\frac{X}{Y}= [\frac{1+2 \epsilon (\omega/ W_n)^2}{(1-(\frac{\omega}{W_n})^2)^2+(2 \epsilon \frac{\omega}{W_n})^2}][/tex]

where;

[tex]\epsilon = 0[/tex]

[tex]W_n = \sqrt { \frac{k}{m}}[/tex]

= [tex]\sqrt { \frac{100*32.2}{200}}[/tex]

= 4.0124

replacing them into the above equation and making X the subject of the formula:

[tex]X =[/tex] [tex]Y * \frac{1}{\sqrt{(1-(\frac{\omega}{W_n})^2)^2})}}[/tex]

[tex]X =[/tex] [tex]0.05 * \frac{1}{\sqrt{(1-(\frac{4 \pi}{4.0124})^2)^2})}}[/tex]

[tex]X =[/tex] [tex]5.676*10^{-3} \ mm[/tex]

Therefore; If there is no damping, the amount of transmitted vibration that the microscope experienced is   = [tex]5.676*10^{-3} \ mm[/tex]