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When two soap bubbles merge, the larger is inflated by the smaller until they form a single bubble. Answer the following questions using \gamma = 0.0415 N/m as the surface tension of the soapy water.What is the gauge pressure inside a soap bubble with a 1.95 cm radius?What is the gauge pressure inside a second soap bubble, with a 3.85 cm radius?If the two bubbles above touch and merge, what is the gauge pressure inside the single bubble they form, assuming no air

Respuesta :

Answer:

Gauge pressure

R(1.95) =4.25

R(3.85) =2.15

R(4.00 merged bubble radius)=2.07

Explanation:

As we know that pressure increment after crossing a curved surface is [tex]\frac{gamma}{radius of curvature at that point}[/tex]

here we cross two surface thus two times of above

thus in soap bubble gauge pressure = [tex]\frac{2*gamma}{radius}[/tex]

  • So in first bubble of radius 1.95

         plug in the values into above formula[tex]\frac{2*gamma}{radius}[/tex]

         [tex]\frac{2*0.0415}{0.0385}[/tex] =4.25 newton/[tex]meter^{2}[/tex]

  • In second bubble of radius 3.85

         Similarly as above[tex]\frac{2*0.0415}{0.0385}[/tex] =2.15 newton/[tex]meter^{2}[/tex]

Finally we merge them to form one bubble then volume of both two combined is equal to final one.

   [tex]\frac{4}{3}[/tex]*π[tex]1.95^{3}[/tex] +    [tex]\frac{4}{3}[/tex]*π[tex]3.85^{3}[/tex] =     [tex]\frac{4}{3}[/tex]*π[tex]radius^{3}[/tex]

 (By volume conservation )

Final radius = 4.00 cm

Putting this value in [tex]\frac{2*gamma}{4.00}[/tex]

Gauge pressure =2.07

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