Answer :
Since youc oncetrate all your force directly towards the moment arm it means that you push it at an angle of your force is directed to the left or the right and I bet that it must be 90 degrees to the bar. Obviuosly, if you are about to push it you will do it straight up but not in a zig zag way. In other words, it should be perpendicular to the arm because the torque can be produced only if force is applied at a constant index (90).
Hope that helps! Regards.
Hope that helps! Regards.