The gravitational field in a region is given by → g = (5 ^ i + 12 ^...

$dV = - \overset{\to}{g} . \overset{\to}{dr}$

$⇒ ∆ V = - \overset{\to}{g} . ∆ \overset{\to}{r}$
= - \left(5\overset{^}{\text{i}} + 12\overset{^}{\text{j}}\right) \cdot \left(7\overset{^}{\text{i}} - 3\overset{^}{\text{j}}\right)
$= - \left(3 5 - 3 6\right) = 1$

$\text{⇒ \Delta}\text{U} = \text{m}\text{\Delta}\text{V} = 2 J$