BIO Should You Walk or Run?? It is 5.0 km from your home to the physics lab. As part of your physical fitness program, you could run that distance at 10 km/h (which uses up energy at the rate of 700 W), or you could walk it leisurely at 3.0 km/h (which uses energy at 290 W). Which choice would burn up more energy, and how much energy (in joules) would it burn? Why does the more intense exercise burn up less energy than the less intense exercise?
Solution 50E Introduction We will first calculate the total time required to reach the destination in each case. Since we know power in each case, we can easily calculate the total energy required in each case. Which one will required more energy will be the choice. Step 1 If we run, the speed isrv = 10 km/h and the distance is d = 5 km, Hence the time taken to reach the physics lab is The power during running is Pr= 700 W So the total energy burned is Step 2 Now if we walk, the speed is w = 3 km/h. Hence the time taken to walk is The power required during walking is Pw = 290 W. So the energy burned during walking is So energy burned during walk is more compared to run. Hence I will walk to physics lab to burn more energy. 6 Walking will burn 3.48 × 10 J of energy.