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- Thread starter Frigus
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We say a system tends to be in lowest energy state that's why a water drop tends to be sphere as it reduces it's surface area the drop will have less surface energy but the energy it reduces by reducing surface area have got converted into internal energy so how it's aim to reach lowest energy state have been reached by becaming a sphere.

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Sir in the rope case the tangential component can be resolved inside but in case of liquid how will the inside force can be resolved into the tangetial component

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The surface tension will create pressure ##P ## inside a spherical droplet. The book "Equilibrium Thermodynamics" by Adkins pp. 39-40 treats this particular case very well. Defining the surface tension ## \gamma=\frac{dW}{dA} ##, we can write ## dW=\gamma \, dA =8 \pi \gamma r \, dr##. We also have ## dW=P \, dV=P \, 4 \pi r^2 \, dr ##. Equating these two expressions for ## dW ## gives ## P=\frac{2 \gamma}{r} ##. ## \\ ## This expression for pressure ## P ## is similar to the expression of the force per unit length in the rope, where, in both cases, the radius ## r ## appears in the denominator.

Sir can you explain it verbally because I want to understand core idea behind it.

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Sir but how can I understand thatPressure is a force per unit area that acts normal to a surface. The ## W ## above is work or energy. Surface tension ## \gamma ## is defined as the work required to increase the area of the surface by one unit, thereby ## \gamma=\frac{dW}{dA} ##.

Sir but from these equations how can I understand that surface tension is tangetial.

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