On September 26, 2002, at 1505 central daylight time, a Cessna 172R, N3510A, collided with corn and the terrain during a simulated forced landing in Greenwood, Illinois. The certified flight instructor (CFI) and the student pilot on board were not injured. The airplane received substantial damage. The 14 CFR Part 91 training flight was operating in visual meteorological conditions without a flight plan. The flight originated from Waukegan, Illinois, at 1435. The CFI reported they were at 4,500 feet mean sea level when a simulated loss of engine power was initiated. He reported that the best glide speed was established and they proceeded to a field that was selected. The CFI reported that at an altitude of about 50 feet above the ground, he instructed the student to go around. He stated that the student hesitated in adding the power, and when he did hear the power increase it did not sound like full power. He continued to state, "I proceeded to say full power and tried to put my hand on the throttle but his hand was still there. I pushed his hand in and then went immediately to reduce the flaps to 20 degrees." He stated he also increased the pitch attitude of the airplane, but by that time they were 10 to 15 feet above the ground. The CFI reported that before a positive rate of climb could be established, the landing gear contacted the corn and the airplane was pulled into the field. The student pilot reported that he hesitated when he was instructed to add full power. Title 14 CFR Part 91.119 - Minimum Safe Altitudes: General states: Except when necessary for takeoff and landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface. (b) Over congested areas. Over any congested area of a city, town, or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft. (c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure. (d) Helicopters. Helicopters may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section if the operation is conducted without hazard to persons or property on the surface. In addition, each person operating a helicopter shall comply with any routes or altitudes specifically prescribed for helicopters by the Administrator.