Question

A small spherical ball falling under gravity in a viscous medium heat the medium due to viscous drage force. The rate of heating is proportional to `r^(n)`. (`r=` radius of the sphere find )`n`.

Answer 1

Correct Answer - 5
Rate of heating `=F_(v).v,F_(V)=6pietarv`
So, `F_(v)` proportional to `r^(3)` hence rate of heating is proportional to `r^(5)`