There are about 6.3 billion people on the planet. Suppose that the world's population gather at one spot on the planet. Assuming each person takes up 1 m^2 of space on avg, the spot is 6.3 billion m^2. Assume that each person's mass is 70 kg on average. Suppose all those people jump at the same time. THe people, while pushing, are in contact with the earth for a time of 0.2 s and leave the ground with a speed of 5 m/s. The distance travelled by the people while pushing the earth is 0.5 m. Mass of the earth is 5.98x19^24 kg. Find the force with which the people push the earth.