Start by drawing a Free-Body-Diagram for the ball.
I have a +x axis to the right and a +y axis upward. There is a weight (w) acting straight downward, a tension (T) acting at 50 degrees above the -x axis, and an applied force (F) of 50 N acting in the +x direction.
Since the ball is in equilibrium we know that
So:
which implies
and
which implies
-Dan