A square loop of edge length 2 m carrying current of 2 A is placed with its edges parallel to the $x y$ axis. A magnetic field is passing through the $x - y$ plane and expressed as $\vec { B } = B _ { 0 } ( 1 + 4 x ) \hat { k }$, where $B _ { 0 } = 5 \mathrm {~T}$. The net magnetic force experienced by the loop is $\_\_\_\_$ N.