When we start to learn about how things move in a straight line, it’s really important to understand some basic math formulas. Here are the main ones you need to know:

1. What is Velocity?
   Average velocity (which we write as $v_{avg}$) shows how fast something is moving. You can figure it out using this formula:
   $v_{avg} = \frac{\Delta x}{\Delta t}$
   Here, $\Delta x$ is how far the object has moved, and $\Delta t$ is how long it took to move that distance.

2. What is Acceleration?
   Acceleration (notated as $a$) tells us how quickly something's speed is changing. It can be calculated with this formula:
   $a = \frac{\Delta v}{\Delta t}$
   In this case, $\Delta v$ is the change in speed.

3. Equations of Motion:
   There are some important equations we use when acceleration stays the same. These are super helpful for figuring out problems:

   • First equation: $v = u + at$
     (Here, $u$ is the starting speed)
   • Second equation: $s = ut + \frac{1}{2}at^2$
     (In this one, $s$ is how far the object has moved)
   • Third equation: $v^2 = u^2 + 2as$

These equations are great tools. They help us guess how an object will move when it speeds up or slows down at a steady rate. This makes them really useful for solving different kinds of problems in physics.