Using Equations for Linear Motion at Constant Acceleration

[Miike012]

When would I use the following equations?

x=x(initial) + V*t

V(av) = 1/2( V(initial) + V)

These equations are used for objects moving in a linear motion at constant acceleration correct?

my book says that I will most likely use the following equations...


but why are the two above equation not important?

 

[Doc Al]

When would I use the following equations?

x=x(initial) + V*t

This one's for constant velocity motion. Note that it's a special case of the second equation on your list, when a = 0.

V(av) = 1/2( V(initial) + V)

This is good for constant acceleration. Note that it's related to the third equation on your list, which is just distance = average velocity X time.

These equations are used for objects moving in a linear motion at constant acceleration correct?

The first has acceleration = 0, but the second one is very useful.

my book says that I will most likely use the following equations...


but why are the two above equation not important?

They are already included, as I note above.