In a written statement, the certified flight instructor (CFI) reported that the purpose of the flight was for the student pilot to practice simulated engine failures. The flight proceeded to mountainous area about 15 miles from the base airport. Three simulated engine failures were performed without mishap and the student setup for a fourth attempt. The airplane descended to about 100 feet above ground level (agl) and the student configured the airplane for a go-around by adding power and pitching the nose upward. Several seconds later the airplane collided with terrain. In the section titled "RECOMMENDATION" in the NTSB Pilot/Operator Report, form 6120.1/2, the CFI stated that accident could have been prevented if the go-around was initiated at a higher altitude. The CFI further added that there were no preimpact mechanical malfunctions or failures with the airframe or engine.