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4.2 friction — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics4.2 friction1 Mark
MCQ
Acceleration of block $A$ varies with time as shown in figure the value of coefficient of kinetic friction between block $A$ and $B$ is the value of coefficient of kinetic friction between block $A$ and $B$ is .............. 
  • ✓
    $0.5$
  • B
    $0.6$
  • C
    $0.4$
  • D
    None of these
✓

Answer

Correct option: A.
$0.5$
a
(a)

Given: acceleration of block $A$ varies with time as shown in figure To find the value of coefficient of kinetic friction between the block $A$ and $B$ Solution:

Force is applied on block $B$. The moment when the block $A$ starts sliding is the moment when the applied force $F$ is greater than the frictional force between the two blocks.

Apply Newton's Second law of motion we get

$\operatorname{ma}_i=\mu g m$

$\Rightarrow a _{\Lambda}=\mu g$

$\Rightarrow 4.9=\mu(9.8)$

$\Rightarrow \mu=0.5$

is the value of coefficient of kinetic friction between the block $A$ and $B$

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