Question

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. $m \sqrt{g^{2} + a^{2}} - ma$
• C. $m \sqrt{g^{2} + a^{2}} + ma$
• D. $m (g + a)$

Answer 1

Answer: (C)

$m \sqrt{g^{2} + a^{2}} + ma$

Answer 2

Applying Newton?? law along string
$T - m \sqrt{ a ^{2}+ g ^{2}}= ma$
$T = ma + m \sqrt{ a ^{2}+ g ^{2}}$