I believe the answer is D. <span>The hypothesis is revised and another experiment is conducted.</span>
Answer: 
Explanation:
The equation to calculate the center of mass 
of a particle system is:
In this case we can arrange for one dimension, assuming the geometric center of the Earth and the ladder are on a line, and assuming original center of mass located at the Earth's geometric center:
Where:
is the mass of the Earth
is the mass of 1 billion people
is the radius of the Earth
is the distance between the center of the Earth and the position of the people (2 m above the Earth's surface)
This is the displacement of Earth's center of mass from the original center.
Answer:
An acceleration of 5m/s^2 means that the velocity of a body is increasing by 5m/s per second in a certain direction
Explanation:
