To address your points:
a) Gravity is present wherever mass is present. Every massive object is attracting every other massive object. The standard view is that mass has existed since the big bang; not something that evolved over substantial time. Mass accumulates to form stars and planets because of gravity. They could not exist without gravity. Gravity came before planets and stars.
b) Every substance on Earth, including you, contributes to the gravity of this planet. Adding more mass increases gravitational attraction. There is no chance or luck involved: gravity exists.
c) Adding mass increases the gravitational attraction exerted by a body. Removing mass decreases the attraction. Material falling to Earth changes Earth’s gravitation by a minuscule amount, as does loss of material like space probes or the outer atmosphere.
d) The gravitational field strength is not constant over the Earth. It varies with altitude and the presence of mass concentrations in the Earth for example.
e) In common logic the apple falls to Earth, but in reality the Earth also moves toward the apple. The force between them is identical… it just accelerates the much more massive Earth much less. It is all about mass and distance.
f) Mass causes gravity and applies to rocks, people, apples, balloons and clouds in the same way. The force applied by gravity can be opposed by other forces. In the case of a hot air balloon the opposition comes from the difference in air pressure between the top and bottom of the balloon (buoyancy). Aircraft do this with lift generated by wings. An object dropped on Earth falls toward the Earth because it is most strongly attracted in that direction. An object dropped on the Moon (yes the experiment was done) falls toward the Moon for the same reason. The Moon falls toward the Earth (orbit) because the attraction of the earth is stronger than the attraction of the Sun… but the attraction to the Sun is there. Objects placed about 1.5 million kilometres toward the Sun experience roughly equal attraction to the Sun and Earth and tend to stay there (its actually slightly more complicated than that).

a) What causes gravity to be created in this universe/earth? The theory of gravity has been used to explain the work of the support of the universe in order to enable the universe to maintain its operation. What causes gravity to be created since beginning? If the world is formed through evolution, how could gravity come about through the creation of earth/universe?

b) What substance to cause gravity to exist on earth? Is it by chance or by luck? What factors that cause gravity to exist permanently on earth/universe?

c) Would gravity be reduced or increased by external factors/influence?

d) If gravity on earth has to maintained at certain rate or number, what factors that cause the gravity to be stagnant and unchangeable?

e) As apples are always dropped to the earth, the gravity should be from the earth that causes apples to drop. What factors that come from the earth that contributes gravity that causes substance to drop?

f) As apples are always dropped to the earth, the air, cloud, sky and etc. do not seem to have gravity, why is it that gravity is always directed from earth and not elsewhere? What causes it then?

When I started the CMTs were fairly basic. They started tightening them up toward the end of my course when they also moved to using Blackboard to manage much of the interaction. The tests were largely multi-choice and short answers but that does not necessarily mean easy.

Each unit was scheduled so that you had to show progress and submit parts of the work at regular intervals. I cannot remember the exactly timing, but I think I always started work in earnest on the project after the earliest CMT. The “Major Project” units ran slightly differently, with an early justify your project submission and a weekly diary submission.

Apart from one semester I took off work, I did two units at a time with a full-time job. It was a manageable with a bit of discipline. With the projects, you can generally choose a topic to suit your interests and available time. If you have a 50 hr/week job, four kids and a live-in mother-in-law then you might struggle I made heavy use of my daily train to/from work to keep up the reading. The early units (like this one) are no too taxing in any case.

Cheers,
Chris

How did you find the CMTs (Computer Managed Tests) when doing SAO? What are they like? I’m just wondering how I’ll balance the essay, weekly postings, a project and the CMTs all at once over two units while working.

I was thinking I might start in earnest on the projects after the essay is submitted, otherwise I might go insane from work… being a complete newbie does have its pitfalls!

James

I’ve just started the SAO course, and was looking for some examples of projects to help guide me in what they were looking for (I got told they didn’t provide example projects).

Cheers again.