BeboOoO
27-05-2010, 01:06
اهلين كيفكم
الدكتوره طلبت مننا نترجم وانا عطتني اترجم صفحتين وترجمتمن عندي اللي فهمته صفحه والصفحه الثانيه مافهمت شي ورحت لقوقل بس مو مفهووووووم
وابيكم تساعدوني بالترجمه الله يسعدكم
14.9 FORCED VIBRATIONS AND RESONANCE
In Chapter 13 we learned that the energy of a damped oscillator decreases over time because of friction.
Its possible to compensate for this energy loss by applying an external force that does positive work on the system.
For example ,suppose an object –spring system having some natural frequency of vibration f_0is pushed back and forth by a periodic Force with frequency f.
The system vibrates at the frequency f of the driving Force .
This type of motion is referred to as a Forced vibration .
Its amplitude reaches a maximum when the frequency of the driving Force equals the natural frequency of the systemf_0, called the resonant frequency of the system .
Under this condition , the system is said to be in resonance .
In Section 14.8 we learned that a stretched string can vibrate in one or more of its natural modes.
Here again, if a periodic Force is applied to the string, the amplitude of vibration increases as the frequency of the applied Force approaches one of the strings natural frequencies of vibration.
Resonance vibrations occur in a wide variety of circumstances .
Figure 14.20 illustrates one experiment that demonstrates a resonance condition.
Several pendulums of different lengths are suspended from a flexible beam
. If one of them , such as A, is set in motion , the others begin to oscillate because of vibrations in the flexible beam .
Pendulum C, the same length as A, oscillates with the greatest amplitude because its natural frequency matches that of pendulum A (the driving Force).
Another simple example of resonance is a child being pushed on a swing, which is essentially a pendulum with a natural frequency that depends on its length.
The swing is kept in motion by a series of appropriately timed pushes .
For its amplitude to increase, the swing must be pushed each time it returns to the persons hands.
ولكم خااااااالص دعواتي
BeboOoO
الدكتوره طلبت مننا نترجم وانا عطتني اترجم صفحتين وترجمتمن عندي اللي فهمته صفحه والصفحه الثانيه مافهمت شي ورحت لقوقل بس مو مفهووووووم
وابيكم تساعدوني بالترجمه الله يسعدكم
14.9 FORCED VIBRATIONS AND RESONANCE
In Chapter 13 we learned that the energy of a damped oscillator decreases over time because of friction.
Its possible to compensate for this energy loss by applying an external force that does positive work on the system.
For example ,suppose an object –spring system having some natural frequency of vibration f_0is pushed back and forth by a periodic Force with frequency f.
The system vibrates at the frequency f of the driving Force .
This type of motion is referred to as a Forced vibration .
Its amplitude reaches a maximum when the frequency of the driving Force equals the natural frequency of the systemf_0, called the resonant frequency of the system .
Under this condition , the system is said to be in resonance .
In Section 14.8 we learned that a stretched string can vibrate in one or more of its natural modes.
Here again, if a periodic Force is applied to the string, the amplitude of vibration increases as the frequency of the applied Force approaches one of the strings natural frequencies of vibration.
Resonance vibrations occur in a wide variety of circumstances .
Figure 14.20 illustrates one experiment that demonstrates a resonance condition.
Several pendulums of different lengths are suspended from a flexible beam
. If one of them , such as A, is set in motion , the others begin to oscillate because of vibrations in the flexible beam .
Pendulum C, the same length as A, oscillates with the greatest amplitude because its natural frequency matches that of pendulum A (the driving Force).
Another simple example of resonance is a child being pushed on a swing, which is essentially a pendulum with a natural frequency that depends on its length.
The swing is kept in motion by a series of appropriately timed pushes .
For its amplitude to increase, the swing must be pushed each time it returns to the persons hands.
ولكم خااااااالص دعواتي
BeboOoO