A Model of a Two-Factor Economy Figure 4-1: Input Possibilities in Food Production Unit land input aTF, in acres per calorie Input combinations that produce one calorie of food Unit land input alF, Copyright C 2003 Pearson Education, Inc in hours per calorie Slide 4-5Copyright © 2003 Pearson Education, Inc. Slide 4-5 // Input combinations that produce one calorie of food Unit land input aTF , in acres per calorie Unit land input aLF , in hours per calorie A Model of a Two-Factor Economy Figure 4-1: Input Possibilities in Food Production