Venice was located in an ideal position to trade with the west the east africa south america

I think the answer would be : with the east.

Venice was known in Europe as the part of spice trade. Which means, They have to build a strong relationship with several countries in south Asia , such as Pakistan, India, and Indonesia because they were the largest producers of spice in the world.

Why the planet stays in orbit is because of inertia (object stays in motion until a force changes it’s motion) also the atmosphere and gravity!