An object is being acted upon by three forces and moves with a constant velocity. One $\mathrm{}$ force is $60$ N along the $+$x$-$axis, the second is $75$ N along a direction making a 

 counterclockwise angle of $150$ degree with the $+$x$-$axis. 

$($a$)$ What is the magnitude of the third force? 

$($b$)$ What is the direction of the third force, measured clockwise from the $+$x$-$axis?

. 

 

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