Ametal bar with length oa = l is rotating in a counter-clockwise manner about the point o with a constant angular velocity ω. there is a constant magnetic field b directed out of the paper. l +q c v a ω o b b b the length of the bar is 10 m and the magnitude of the magnetic field is 2 t . the speed of the bar at point c is 81 m/s, and the length of oc = 7 m . determine the magnitude of the potential difference |vo − va| .