When a 20-lb weight is suspended from a spring, the spring is stretched a distance of 1 in. Determine the natural frequency and the period of vibration for a 30-lb weight attached to the same spring

Respuesta :

Answer:

natural frequency = 2.55 Hz

period of vibration = 0.3915 s

Explanation:

given data

weight = 20 lb

distance = 1 in = [tex]\frac{1}{12}[/tex] ft

weight = 30 lb

to find out

Determine the natural frequency and the period of vibration

solution

we first calculate here stiffness k by given formula that is

k = [tex]\frac{weight}{diatnace}[/tex]  ..........1

k = [tex]\frac{20}{1/12}[/tex]

k = 240 lb/ft

so

frequency = [tex]\sqrt{\frac{k}{m} }[/tex]   ..................2

put here value k and mass m = [tex]\frac{weight}{g}[/tex]

frequency = [tex]\sqrt{\frac{240}{30/32.2} }[/tex]  

frequency = 16.05 rad/s

and

period of vibration = [tex]\frac{2* \pi }{frequency}[/tex]

period of vibration = [tex]\frac{2* \pi }{16.05}[/tex]

period of vibration = 0.3915 s

and

natural frequency = [tex]\frac{1 }{period of vibration}[/tex]

natural frequency = [tex]\frac{1 }{0.3915}[/tex]

natural frequency = 2.55 Hz