The diagram shows a small ball of mass m=0.280kg that is attached to a rotating vertical bar by means of two massless strings of equal lengths L=1.10m. The distance between the points where the strings are attached to the bar is D=1.56m. The rotational speed of the bar is such that both strings are taut and the ball moves in a horizontal circular path of radius R at constant speed v=3.65m/s.

(a) Determine the magnitude and direction of the net force that is acting on the ball when it is in the position shown in the diagram.

(b) Determine the magnitude of the tension T1 in the upper string and the magnitude of the tension T2 in the lower string.

(c) Determine the speed of the ball at which the tension T2 becomes zero.

i'm not sure how to go about solving this problem, i've never done anything like it...help?