Elements of natural philosophy (Volume 2-3) . Conclusionrespecting NEW DIVERGENCE AND INFLEXION OF SOUND. Any disturbedparticle causessubsequentdisturbance inanother; Same true for allparticles in awave front: Illustration; Fig. 30. § 63. We have seen that every disturbance of a mole-cule at one time is truly a cause of disturbance of an-other molecule at some subsequent time. All the mole-cules in a wave front become, therefore, simultaneouslycentres of disturbance, from each one of which a waveproceeds in a spherical front, as from an original dis-turbance of a single molecule. Thus,in the w
Elements of natural philosophy (Volume 2-3) . Conclusionrespecting NEW DIVERGENCE AND INFLEXION OF SOUND. Any disturbedparticle causessubsequentdisturbance inanother; Same true for allparticles in awave front: Illustration; Fig. 30. § 63. We have seen that every disturbance of a mole-cule at one time is truly a cause of disturbance of an-other molecule at some subsequent time. All the mole-cules in a wave front become, therefore, simultaneouslycentres of disturbance, from each one of which a waveproceeds in a spherical front, as from an original dis-turbance of a single molecule. Thus,in the wave front A B, a moleculeat x becomes a new centre of dis-turbance as soon as the wave frontreaches it; and if with a radiusequal to a circle be described,this circle will represent a section Cof the spherical wave front proceed-ing from #, with the velocity I7, atthe end of the interval of time de-noted by t. And the same bein^rtrue for the molecules x\ x\ &c, of the primitivewave, there will result a series of intersecting circles. ELEMENTS OF ACOUSTICS. 71 having equal radii, and the larger circle A! B Construction of ,, . , resultant wave tangent to ail these smaller circles, will obviously be a front;section of the main wave front at the expiration of theinterval t, after it was at A B. Any molecule situatedat the intersection of the smaller circles will obviouslybe agitated by the waves transmitted to it from mole-Eesultantcules at their respective centres ; and the resultant clis- ^placement ofplacement will, §55, §56, be the algebraic sum of tlieapaltlc1displacements due to each when superposed. Hence, to find the disturbing effect of any wave upona given molecule at a given time, divide the wave intoa number of small parts, consider each part as a centreof disturbance, and find by summation the aggregate ofall the disturbances of the given molecule by the wavescoming from all the points of the great wave. The cause which makes the disturbance of a singlemolecule
Size: 1106px × 2259px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmechanics, booksubjectopticsandphoto
