Now we come to the problem of how something falls through the air. Not very happily if it we're talking about a camel. So let's talk about something else instead. What is the position of a baseball as a function of time? What is its velocity?
Free fall is an example of motion with constant acceleration. We already dealt with this in one dimension but things look a lot more exciting in two dimensions. Baseball is not an exciting sport in one dimension, but in three dimensions it seems to have a mesmerizing effect on certain people.
In the case of free fall, the acceleration vector points vertically
downward. Again, its value has a magnitude of about 
.
We can follow the same line of reasoning we did in one dimension. Everything is the same except that now we have vectors. So we can march through all the same steps, and come up with a very similar set of equations. Eq. 3.11 becomes
Here 
is the initial velocity of an object at 
.
To get the position vector 
as a function of time is equally easy to
generalize. Instead of eq. 3.14 we have
Here 
is the initial position vector of the object.
