When liquid medicine of density ρ is delivered with a dropper, a nearly spherical drop forms at the opening. For a drop of radius R and dropper-opening radius r, detachment occurs when the upward vertical component of surface-tension force becomes smaller than the drop weight.
Physics · Properties of solid and fluid
When liquid medicine of density ρ is delivered with a dropper, a nearly spherical drop forms at the opening. For a drop of radius R and dropper-opening radius r, detachment occurs when the upward vertical component of surface-tension force becomes smaller than the drop weight.
Sub-question 1
If the dropper opening has radius r, find the vertical surface-tension force on a drop of radius R, assuming r ≪ R.
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Sub-question 2
If r = 5 × 10 m, ρ = 10 kgm , g = 10 ms , T = 0.11 Nm , the radius of the drop when it detaches from the dropper is approximately.
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Sub-question 3
After the drop detaches, its surface energy is
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