How Does the Average Frequency (w1+w2)/2 Affect Undamped Forced Vibrations?

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In summary, forced undamped vibration is the continuous oscillation of a system driven by an external force without any resistance. An example of this is a child on a swing. The main difference between forced undamped vibration and forced damped vibration is the presence of resistance or damping in the latter. Forced undamped vibration has various applications in engineering and can be described mathematically using a second-order differential equation.
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as we know ,the equation to the undamped forced vibration is
x=Asin{(w1+w2)/2}sin{(w1-w2)/2},the symbols have their usual meaning..but i can't understand how (w1+w2)/2 comes in picture in the phasor diagram...also its significance
 
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The equation for undamped forced vibration, x=Asin{(w1+w2)/2}sin{(w1-w2)/2}, represents the displacement of a vibrating object at any given time. The symbols in the equation have their usual meanings, where A is the amplitude, w1 is the natural frequency of the system, and w2 is the frequency of the external force.

The term (w1+w2)/2 in the equation represents the average frequency of the system. This average frequency is important because it determines the overall behavior of the system. When the average frequency is close to the natural frequency of the system, the amplitude of vibration will be large, resulting in a phenomenon known as resonance. This can be seen in the phasor diagram, where the amplitude of the vibration is represented by the length of the phasor.

On the other hand, if the average frequency is significantly different from the natural frequency, the amplitude of vibration will be smaller. This is because the external force is not in sync with the natural frequency and is unable to transfer energy efficiently to the system.

In summary, the term (w1+w2)/2 in the equation and its representation in the phasor diagram help us understand the behavior of the system and how the external force affects it. It is a crucial factor in determining the amplitude of vibration and can lead to resonance or dampening of the vibration.
 

FAQ: How Does the Average Frequency (w1+w2)/2 Affect Undamped Forced Vibrations?

What is forced undamped vibration?

Forced undamped vibration refers to the oscillation or movement of a system that is continuously driven by an external force or energy source, without any damping or resistance.

What is an example of forced undamped vibration?

A classic example of forced undamped vibration is a child on a swing, where the child's motion is driven by the force of their legs pumping back and forth without any resistance or friction.

How does forced undamped vibration differ from forced damped vibration?

The main difference between forced undamped vibration and forced damped vibration is that the latter experiences resistance or damping, which results in a decrease in amplitude over time, while the former maintains a constant amplitude.

What are the applications of forced undamped vibration?

Forced undamped vibration has various applications in engineering, such as in the design and analysis of structures, machines, and vehicles. It can also be used in musical instruments, earthquake engineering, and other fields that involve oscillatory motion.

How is forced undamped vibration mathematically described?

Forced undamped vibration can be described by a second-order differential equation, where the external force is equal to the mass multiplied by the acceleration. This equation can be solved using mathematical methods such as the method of undetermined coefficients or Laplace transforms.

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