An object falling through a fluid is observed to have acceleration given by a = g -bv where g = grav

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9-1.Fluid Mechanics

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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

$\frac{g}{b}$

B

$\frac{b}{g}$

C

$bg$

D

$b$

Solution

Here, $a=g-b v$

When an object falls with constant speed $v_{c},$ its

acceleration becomes zero.

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

Standard 11

Physics

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(JEE MAIN-2020)