Question

An object falling through a fluid is observed to have acceleration given by a = g – bv where g = gravitational acceleration and b is constant. After a long time of release, it is observed to fall with constant speed. The value of constant speed is

• A. $\frac { \mathrm { g } } { \mathrm { b } }$
• B. $\frac { b } { g }$
• C. bg
• D. b

Answer 1

Answer: (A)

$\frac { \mathrm { g } } { \mathrm { b } }$

Answer 2

Here , a = g – by

When an object falls with constant speed $\mathrm { V } _ { \mathrm { c } }$ its accelerations becomes zero.

$\therefore \mathrm { g } - \mathrm { bv } _ { \mathrm { c } } = 0$ or $\mathrm { v } _ { \mathrm { c } } = \frac { \mathrm { g } } { \mathrm { b } }$