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The gravitational field in a region is given by \vec{g}= 5N/kg \: \hat{i}+12N/kg\: \hat{j}.The change in the gravitational potential energy ( in joules) of a particle of mass 2 kg when it is taken  from the  origin to  a  point (7 m,-3 m) is :

Option: 1

2


Option: 2

13


Option: 3

-71


Option: 4

71


Answers (1)

best_answer

 

 

Relation between gravitational field and potential  is given by

\vec{E}=-\frac{dV}{dr}

So V=-\int E.dr

and U=mV

So \\ \Delta U=-\int m E.dr\\ \Delta U= -2*\int (5\vec{i}+12\vec{j}).(dx\vec{i}+dy\vec{j}) \Delta U=-2* \int_{0}^{7} 5dx-24 \int_{0}^{-3}dy \\ \Delta U=-2[5*(7-0)+12*(-3)]=2J

Posted by

Ritika Kankaria

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