1. Velocity is a vector which includes speed and direction.
correct.
but the direction such as north or south or whatever
is not used unless needed.
2. Acceleration is change in velocity.
correct.
but over time. ie ... ms^2
3. Change of speed with constant direction = acceleration.
correct.
4. Change of direction with constant speed = acceleration.
correct.
5. A body orbiting at constant speed is constantly accelerating.
correct.
6. Gravity is not a force that holds an orbiting body as though it were on a string.
correct.
gravity is the force that holds a orbiting body.
but not like it was on a string.
to achieve an orbit around a body , gravity is the force
that must be counteracted by the force of the orbiting
objects mass x its velocity.
the velocity for instance is like the tension on the string.
if the orbiting object increases velocity the tension on the string increases , if the string were elastic then the orbiting object would gain altitude.
if the orbiting object decreases velocity the tension on the string decreases , if the string were elastic the orbiting object would loose altitude.
f=mv
for instance a object that normally weighs 1 kg on the earths surface must achieve a orbital velocity that would counteract the pull of gravity that it feels ( 1 kg on earths surface )
but less as the orbit increases , in order to counteract the pull of gravity and maintain a given orbital distance around the body being orbited the orbiting object must achieve a certain velocity in order to achieve an angular acceleration that is the product of the orbiting objects velocity and
the orbiting objects mass and the gravitational pull between the orbited body and the orbiting object that balances the
forces acting on the orbiting object thereby causing the orbiting object to maintain a certain orbital height as it
constantly accelerates towards the earth.
a orbit is simply a balancing act.
7. Gravity alters the geometry of spacetime such that it becomes curved.
no belief = no comment.
8. The curve thus formed is a geodesic, and is defined as the most direct path from A to B in curved spacetime.
no belief = no comment.
9. Thus, a geodesic is equivalent to a straight line in flat (non-curved) spacetime.
no belief = no comment.
10. A body travelling at constant speed in a straight line is not accelerating.
correct.
11. It should be reasonable to argue that a body following a geodesic at constant speed is not accelerating.
incorrect.
you cannot follow a geodesic without accelerating towards
or away from the sections of a geodesic shape as you travel above the sections that make up the geodesic shape.
12. It should, therefore, be reasonable to conclude that an orbiting body is not accelerating.
incorrect.
there can not be an orbiting body that does not accelerate
around a orbited body.
an object will travel in a straight line if it is
not accelerated in another direction away from the straight line.
