Estimate and determine the order of magnitude of the circumference of the earth in miles and the speed of a sailboat in miles per hour. the earth's circumference is 10^4 mile and the the speed of a sailboat is 10^1 mile/hour.

The time it would take to sail around the world in a sailboat is 1000 hour.        

Explanation:

It is given that,    

The circumference of the Earth,

The speed of a sailboat,

We need to find the time it would take to sail around the world in a sailboat. It can be calculated using the definition of velocity. It is given by :

t = 1000 hour

So, the time it would take to sail around the world in a sailboat is 1000 hour. Hence, this is the required solution.

b. latent learning (the word "latent" itself means something that exists but isn't obvious, only under certain conditions! )

3. dark matter

empty space could also be a simple vacuum