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AP EAMCET · PHYSICS · Mechanical Properties of Fluids

A rain drop of radius \(r\) is falling through air, starting from rest. The work done by all the forces on the drop, when it attains terminal velocity, is proportional to

  1. A \(r^3\)
  2. B \(r^7\)
  3. C \(r^5\)
  4. D \(r^4\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(r^7\)

Step-by-step Solution

Detailed explanation

Given, radius of rain drop \(=\mathrm{r}\) Since, rain drop starts falling from rest, hence its initial speed, \(u=\mathbf{0}\) Final velocity of rain drop is equal to the terminal velocity \(v\), which is given by \(v=\frac{2 g r^2(\rho-\sigma)}{9 \eta}\) where,…