On October 6, 1997, approximately 1000 eastern daylight time, a Cessna 120, N1856N, was substantially damaged when it nosed over during an aborted takeoff from a private grass runway near Prince George, Virginia for a local flight. The certificated private pilot and passenger were not injured. Visual meteorological conditions prevailed at the time and no flight plan was filed for the personal flight conducted under 14 CFR Part 91. The pilot stated that the east/west direction grass airstrip, from which he was departing, had a length of 2400-2500 feet with 40 foot trees located on the western end. The pilot proceeded to takeoff from the end of the airstrip in a westerly direction and rotated the airplane about 1000-1200 feet down the runway at 60 miles per hour indicated airspeed. The airplane climbed to 4 feet above the ground, then would not climb any higher and continued to travel down the runway for another 400-500 feet where the pilot elected to abort the takeoff by reducing engine power. The airplane descended, touched down on loose dirt and nosed over coming to rest inverted. Upon exiting the airplane, the pilot asked the passenger if he had applied pressure to the brakes that were located on his side of the cockpit, to which he responded that he did not know where they were. The airplane had brakes pedals located on both sides of the cockpit. The pilot reported no mechanical problems with the airplane.