A student eats a breakfast consisting of a bowl of cereal and milk, containing a total of 3.15 X 10² Calories of energy. He wishes to do an equivalent amount of work In the gymnasium by doing curls with a 24.0-kg barbell (see figure). How many times must he raise the weight to expend that much energy? Assume that he raises it through a vertical displacement of 0.400 m each time, the distance from his lap to his upper chest.

How many sprints from rest to a speed of 4.1 m/s would a 64-kg woman have to complete to burn off 5.0 X 10² Calories? (Assume 100% efficiency in converting food energy to mechanical energy. Ignore the energy expenditure of slowing down.) sprints