Only two forces act on a 3.1 kg object that moves with an acceleration of 3.3 m/s2 in the positive direction of a y axis.

Only two forces act on a 3.1 kg object that moves with an acceleration of 3.3 m/s2 in the positive direction of a y axis. If one of the forces acts in the positive direction of an x axis and has a magnitude of 8.1 N, what is the magnitude of the other force?