On June 4, 1999, about 1045 eastern daylight time, a Cessna 150M, N3773V, registered to a private individual, was landed hard at Barwick La Fayette Airport, La Fayette, Georgia. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR part 91 instructional flight. The airplane was substantially damaged and the private-rated pilot and student pilot sustained minor injuries. The flight originated about 1 hour earlier from Barwick La Fayette Airport, La Fayette, Georgia. The private-rated pilot-in-command (PIC) stated that the purpose of the flight was for the airplane owner (student pilot) to follow him through on the flight controls. The flight departed, performed two landings, then flew to a nearby city, and returned to the departure airport for another landing. While on final approach with the flaps fully extended; the PIC was manipulating the throttle control and the student was manipulating the flight controls. The PIC stated that the student flared too high and advised the student of this. The student then reportedly pushed forward on the control column but before the PIC could react, the airplane then landed hard in a nose-low attitude. The PIC further stated that there was no preimpact failure or malfunction of the flight controls or of the engine. The student stated that he does not recall pushing forward on the control column but did state that he did not hear the stall warning horn. According to the airplane owner, the stall warning system operationally checked satisfactory after the accident.