5.3. Your instructor will give you an unknown mass. Hang this mass from one of the pulleys. Hang a 300-gram mass from a second pulley that is placed at an angle of between 110 and 150 from the pulley that has the unknown mass. Use the force probe to find the magnitude and direction of the third force acting on the ring. As before, draw a free-body diagram, and use it to construct a scaled vector sum. This time, you do not know the magnitude of one of the vectors but you know the vector sum should be zero. 90 __ I 130 Ring 0 -0 270 Once you have made a prediction based on your scaled diagram, measure your unknown mass