A uniform bar has mass $0\mathrm{.}0140$ kg and is $30\mathrm{.}0$cm long. It pivots without friction about an axis perpendicular to the bar at point a in $($Figure $1).$ The gravitational force on the bar acts in the $$y$-$direction. The bar is in a uniform magnetic field that is directed into the page and has magnitude $0\mathrm{.}150$ B $.$

Figure

$1$ of $1$

Part A

What must be the current I in the bar for the bar to be in rotational equilibrium when it is at an angle $40\mathrm{.}0$ above the horizontal? Use the fact that $=12$IBL$2$ for a uniform bar of length L carring a current I in a magnetic field B$.$

Express your answer with the appropriate units.