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Mechanical Properties Of Fluids

Question
CBSEENPH11020534

When two displacements represented by straight y subscript 1 space equals space straight a space sin space space left parenthesis ωt right parenthesis space and space straight y subscript 2 space equals space straight b space cos space left parenthesis ωt right parenthesis are superimposed, the motion is 

  • not a simple harmonic

  • simple harmonic with amplitude a/b

  • simple harmonic with amplitude square root of straight a squared plus straight b squared end root

  • simple harmonic with amplitude fraction numerator left parenthesis straight a plus straight b right parenthesis over denominator 2 end fraction

Solution

C.

simple harmonic with amplitude square root of straight a squared plus straight b squared end root

straight y subscript 1 space equals space straight a space sin space ωt
straight y subscript 2 space equals space straight b space cos space ωt space equals space straight b space sin space open parentheses ωt space plus straight pi over 2 close parentheses
The space resultant space displacement space is space given space by space
straight y equals straight y subscript 1 space plus straight y subscript 2 space equals space square root of straight a squared plus straight b squared end root space sin space left parenthesis ωt space plus straight ϕ right parenthesis
Hence comma space the space motion space of space superimposed space wave space is space simple space harmonic space with
amplitude space square root of straight a squared plus straight b squared end root