ure A nd t full in ate ata 19. (2) Benny must replace lost heat energy using chemical energy from her food. According to the USDA carrots have an energy density of about 0.5 "food calories" per gram, or about 2100 J/g. How many grams of carrot would Benny need to eat, to replace the energy she used raising her body temperature in the previous question? 199.249 of carrots. Mechanical Equivalence of Heat Energy To get more context for how energetically expensive it is for a mammal to maintain a constant high body temperature, let's explore another way Benny might prefer to use her energy - by hopping around! To do this, we need to quantify the mechanical equivalence of heat energy. This requires a more sophisticated experiment than just shaking up a thermos of water. Relevant equations & parameters: Gravitational potential energy (in joules): PEG-MhAT (PEG= potential energy [J];M= mass of suspended object [kg]; h= height [m]; g= rate of acceleration due to gravity [m/s]) Parameter Rate of an object's acceleration due to Earth's gravity, g Value Units 9.8 m/s 20. (1) The energy it takes for Benny to hop 1 meter high is equal to her body's gravitational potential energy at the highest point of her jump. Based on the equation for gravitational potential energy (above), how much chemical energy does Benny need to make a single hop 1m high? How to solve it: 3 kg x 1 m 9.8 m/s = 29.4 J 1229.40 21. (2) Based on your calculations, how many 1m hops could Benny have made with the same energy she used to increase her body temperature by 1C? 22. (2) Humans and rabbits heat their bodies using chemical energy from food. Human foods can contain a LOT of chemical energy. A single Oreo cookie contains 55 "food calories", which equals 222 kJ of chemical energy (= 222,000 J). How many Oreo cookies would a 55 kg (121 lb) student need to eat, to raise their body temperature by 1 C? 55 kg x 1000 g 1 kg X 4.18 J 9.C x 1C X 1 Oreo 222,000 J 1.04 re Oreos 23. (2) How many times could a student weighing 55 kg jump a half-meter in the air, using the amount of chemical energy from a single Oreo cookie? Page 6 of 7 81