\(I = - \frac{{dv}}{{dr}}\)
\(v = - \left[ {\int\limits_0^x {{I_x}dx + \int\limits_0^y {{I_y}dy} } } \right]\)
\( = - \left[ {{I_x}.x + {I_y}.y} \right]\)
\( = - \left[ {5\left( {7 - 0} \right) + 12\left( { - 3 - 0} \right)} \right]\)
\( = - \left[ {35 + \left( { - 36} \right)} \right] = 1J/kg\)
i.e., change in gravitational potential \(1J/kg\)
Hence change in gravitational potential energy \(1J\)