An object having spherical shape of radius 'r' experiences a retarding force F from a fluid of coefficient of viscosity 'η' when moving through the fluid with speed 'v'. What is the ratio of retarding force to speed?
Correct answer: C. 6πη r
- A. 6πη r2
- B. 6πη/r2
- C. 6πη r
- D. 6πη/r
Explanation
Retarding force=6πη r v. ratio of retarding force to speed (v) would be (6πη r v)/v which equals 6πη r.
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