44-kg woman cheats on her diet and eats a 695-calorie (695 kcal) jelly doughnut for breakfast. (a) how many joules of energy are the equivalent of one jelly doughnut? j (b) how many stairs must the woman climb to perform an amount of mechanical work equivalent to the food energy in one jelly doughnut? assume the height of a single stair is 15 cm. stairs (c) if the human body is only 28% efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast? stairss..com/question/index? qid=20091118160038aazycd1

(a) how many joules of energy are the equivalent of one jelly doughnut?

We are already given the energy which is equal to 695 kcal. We know that in 1 kcal, there is 4184 Joules, therefore:

Energy = 695 kcal * (4184 J / 1 kcal)

Energy = 2,907,880 J

(b) how many stairs must the woman climb to perform an amount of mechanical work equivalent to the food energy in one jelly doughnut? assume the height of a single stair is 15 cm. stairs

We can solve this by using the Potential Energy formula:

PE = m g h

2,907,880 J = 44 kg * 9.8 m/s^2 * h

h = 6,743.7 m

So the number of stairs is:

stairs = 6,743.7 m / 0.15 m

stairs = 44,958

(c) if the human body is only 28% efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast?

So the number of stairs will be:

stairs = 44,958 / 0.28

stairs = 160,564

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

laticia draws the diagram below to show earth’s magnetic field.

answer

the arrows to the right of earth should point up.