A bodybuilder lifts a 20-kg barbell a distance of 0.50 m 1000 times. If the energy required for this task is provided by burning fat, how much fat

A bodybuilder lifts a 20-kg barbell a distance of 0.50 m 1000 times. If the energy required for this task is provided by burning fat, how much fat will the bodybuilder consume? (The potential energy lost each time she lowers the weight is dissipated as heat.) Fat supplies 38 MJ of energy per kilogram; this chemical energy is converted to mechanical energy with a conversion efficiency of about 20%.