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4.1 , newtons laws of motion — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysics4.1 , newtons laws of motion1 Mark
MCQ
A bob is hanging over a pulley inside a car through, a string. The second end of the string is in the hand of a person standing in the car. The car is moving with constant acceleration ' $a$ ' directed horizontally as shown in figure. Other end of the string is pulled with constant acceleration ' $a$ ' vertically. The tension in the string is equal to-
  • A
    $m \sqrt{g^2+a^2}$
  • B
    $m \sqrt{ g ^2+ a ^2}- ma$
  • ✓
    $m \sqrt{g^2+a^2}+m a$
  • D
    $m ( g + a )$
✓

Answer

Correct option: C.
$m \sqrt{g^2+a^2}+m a$
c
(c)

Applying Newton's law along string

$\Rightarrow T - m \sqrt{ g ^2+ a ^2}= ma$

$\text { or } T = m \sqrt{ g ^2+ a ^2}+ ma$

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