A small steel ball falls through a syrup at a constant speed of `10cms^-1`. If the steel ball is pulled upwards with a force equal to twice its effective weight, how fast will it move upwards?

Explanation

`6pi eta r v^(2)=mg^(1)" (effective weight)"`
Let `W_(e)="effective weight and "6pi eta r=K`
`"In equilibrium, "w_(e)=kv" -------(1)"`
Again, `2w_(e)=kv^(1)" ----------(2)"`
From Eqs. (i) and (ii) `v^(l)=v=1.0m//s`