A 83.55kg woman walked a 5k race in 53.33 minutes. 1. what was her average speed

ID: 2100623 • Letter: A

Question

A 83.55kg woman walked a 5k race in 53.33 minutes.

1. what was her average speed in m/s?

2. what was her average momentum?

3. How much kinetic energy per second did she have based on this speed?

4. How much total kinetic energy was used to complete the race?

5. How much power did it take to complete the race?

6. She burned 323.37 calories, convert this to Joules.

7. based on answers from #4 and#6 how efficient was her body at converting food energy into mechanical energy?

High points awarded for each equation shown please!!!!!!!

1) Average Speed = 5000/(53.33 * 60) = 1.562 m/s

2) Average momentum = 83.55 * 1.562 = 130.555 kg m/s

3) KE per second = 0.5 * 83.55 * 1.562^2 / (53.33 * 60) = 0.031 J/s

4) Total KE = 0.5 * 83.55 * 1.562^2 = 101.92 J

5) Power = 0.031 W

6) 1 calorie = 4.204 J

Hence 323.37 Calorie = 1359.447 J of energy

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