Part A

A uniform bar has mass $0\mathrm{.}0180$ 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 $0\mathrm{.}250$ B $.$

What must be the current I in the bar for the bar to be in rotational equilibrium when it is at an angle $35\mathrm{.}0$ above the horizontal? Use the fact that $=\frac{1}{2}IB{L}^2$ for a uniform bar of length $L$ carring a current I in a magnetic field $B.$

Express your answer with the appropriate units.

$I=$

$$

$$

Units input for part A

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