If for the same disk of Problem, the trial weight of 2 oz is placed at 135° cw from the reference mark, the new unbalance is found to be 4.3 mm at 11 e CW. Show that the correct balance weight is unchanged.

Problem

A thin disk is supported on spring-mounted bearings with vibration pickup and strobotac, as shown in Figure. Running at 600 rpm ccw, the original disk indicates a maximum amplitude of 2.80 mm at 45° cw from a reference mark on the disk. Next a

trial weight of 2.0 oz is added at the rim in a position 91.5° cw from the reference mark and run at the same speed. If now the new unbalance is 6.0 mm at 80° cw from the reference mark, determine the position and weight necessary to balance the original disk.