Question

After terminal velocity is reached, the acceleration of a body falling through a viscous fluid is:

• A. $\text{Zero}$
• B. $g$
• C. Less than $g$
• D. Greater than $g$

Answer 1

The correct option is A $\text{Zero}$

Terminal velocity is achieved when weight of the body is balanced by the drag force $\left(F_D\right)$ and bouyant force$\left(F_B\right)$.
At terminal velocity i.e $V=V_T$,
$W=F_B+F_D$
Since $F_{\text{net}}=0$ on the body, the body continues to move with constant velocity $\left(V_T\right)$ thereafter.
$\therefore a=0$