When solving kinematics problems, there are five variables,
Notice that the "x" subscript has been added. This is additional information to indicate that these vectors are in the horizontal direction (left and right).
There are 4 equations that are used,
When solving problems make x_{o} equal to zero. This means that when the description of the motion begins, that's the origin. To make it easy to compare answers, make all the displacement, velocities and accelerations that point to the right positive in the equations. Make all the variables that point left, negative.
Example (Review) 
When a moving car is first seen, it is moving at 10.0 m/s to the right.The car is slammed into reverse. The wheels spin backwards to giving the car a deceleration of 3.0 m/s^{2}. What is the car's displacement after doing this for 8.00 seconds? 
Solution 

Example 2 (Review) 
A bowling ball rolls from right to left with an initial velocity of 5 m/s. If the ball's deceleration is 1.1 m/s^{2} for 2.5 seconds, then what is the ball's position after the 2.5 seconds. 
Solution 

Example #3 (Review) 
When a moving car is first seen, it is moving at 10.0 m/s to the right.The car is slammed into the reverse gear. As the wheels begin to spin backwards the car is given a deceleration of 3.0 m/s^{2}. What is the car's velocity after doing this for 8.00 seconds? (This problem has the same givens as example #1 above.) 
Solution 

