On May 26, 1994, at 1630 central daylight time, a Cessna 152, N757SU, registered to Kansas Aircraft Corp of Olathe, Kansas, and operated by a flight instructor and non pilot-rated passenger, experienced an overrun on runway 17 (2,440' x 75' dry turf) at Cedar Air Park, Olathe, Kansas, while the instructor was demonstrating a downwind landing. The airplane sustained substantial damage. The instructor and passenger reported no injuries. The demonstration flight was operating under 14 CFR Part 91. The flight was operating in visual meteorological conditions. No flight plan was on file. The flight last departed Johnson County Executive Airport, Olathe Kansas, at 1400. The flight instructor stated that he landed longer than normal to leave clearance between himself and a mower on the north end of the runway. He stated that he landed on runway 17 with the prevailing wind of 060 degrees at 8 knots. The witness operating the mower stated the wind to be 360 degrees at 15 knots.