Chapter 10, Problem 34PQ

According to the National Academy of Sciences, the Earth’s surface temperature has risen about 1°F since 1900. There is evidence that this climate change may be due to human activity. The organizers of World Jump Day argue that if the Earth were in a slightly larger orbit, we could avoid global warming and climate change. They propose that we move the Earth into this new orbit by jumping. The idea is to get people in a particular time zone to jump together. The hope is to have 600 million people jump in a 24-hour period. Let’s see if it will work. Consider the Earth and its inhabitants to make up the system.

a. Estimate the number of people in your time zone. Assume they all decide to jump at the same time; estimate the total mass of the jumpers.

b. What is the net external force on the Earth–jumpers system?

c. Assume the jumpers use high-tech Flybar pogo sticks (Fig. P8.32), which allow them to jump 6 ft. What is the displacement of the Earth as a result of their jump?

d. What happens to the Earth when the jumpers land?