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posted by  PhysFL on 11/7/2009 10:03:37 AM  |  status: Closed  |  Earned Karma: 50

Speed Change

Course Textbook Chapter Problem Needs by
Calculus Based Physics Principles of Physics (3rd) by Serway, Jewett N/A N/A 11/11/2009 at 8:00:00 PM
Question Details:
A vibrating source generates a harmonic wave on a string under constant tension. If the power delivered to the string is doubled, by what factor does the speed change?

A)4
B)2
C)1.41
D)no change
E)0.5

Hint:

v = (T/m)1/2.  If the tension is constant the speed is constant.
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posted by watt (MNK) on 11/7/2009 10:20:48 AM  |  status: Live
Asker's Rating: Lifesaver   
Response Details:
Power P α v
 ( P ' / P ) = ( v ' / v )
Given new power P ' = 2 ( original power )
                           P ' = 2P
2P / P = v ' /v
 v ' / v = 2
        v ' = 2v
new speed  v ' = 2 * original speed
So, option ( B ) is correct
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