# Why are vertical and horizontal motion considered independent?

##### 1 Answer

Nov 2, 2016

We know that in motion problems, displacement, velocity and acceleration all are vector quantities. Only for the sake of simplicity these are written as

For sake of completeness these should be written as

We also know that for vector quantities, orthogonal component is always equal to zero as shown below.

For any vector

It follows that for

As such vertical and horizontal components of motion can be treated independently.