The airplane collided with power lines, impacted a roadway and came to rest inverted at about 1300 Pacific time. The Flight Instructor and Student pilot sustained minor injuries; the airplane was substantially damaged. Visual conditions prevailed. The instructor later stated that while on short final to land, she was flying the airplane with the student holding the controls lightly to feel the movement. During the flare, turbulence was encountered. This scared the student pilot, who firmly grabbed the controls and would not release them. The airplane drifted left towards parked airplanes and hangars. The instructor initiated a go-around, added full throttle and tried to steer the airplane back toward the runway, but could not overpower the students grip on the controls. The airplane cleared the hangars but the landing gear got entangled in power lines and the airplane came down nose first onto a street.