PROBLEM SOLVING SUGGESTIONS

Problem-Solving Suggestions for One-Dimensional Constant Acceleration or Velocity Problems

The following statements/equations are valid when an object is moving at a constant speed provided you set the acceleration a = 0, i.e. constant speed is a special case of constant acceleration when the acceleration is zero.
The first thing we know is that generic equation for uniform accelerated apply,

Identifying the Varaibles: One essential operation in solving any problem is turning the verbal statement of the problem into a set of mathematical statements by identifying what is given, what is requested, and what is implied.

Verbal meaning of some of the variables used in the generic kinematic equations.

Variable	Meaning
	Initial or staring position of an object. If the origin is placed at this location then x_o= 0.
	Final location or position of an object.
	The distance an object travels.
	Initial or starting velocity of an object.
	Final velocity of an object.
	The change in object's speed.
	The average velocity of the object.
	The object's acceleration
	The starting time. If the clock is started at this moment then t_o= 0.
	The final time.

In any (kinematic) problem you will know the value of some of these variables and be requested to find the value of others. The only difference between a given and an unknown is your current state of awareness of its value. What is an unknown in one problem may be a given in another problem. A variable switches from an unknown to a known when you find its value (or its value is explicitly given or implied in the verbal statement of the problem).

Each of the generic kinematic equations involves a certain subset of variables and constants used to describe motion.

Note that the different equations in a given set are all identical (provided t_o= 0). They are just expressed in a different structural forms.
The decision of which equation to use in any given problem involves looking at what subset of variables you know and what subset you don't know.

If you know all of the variables but one in some subset, then you can use one of the associated equations in that subset to find the unknown variable.

Also observe that it is not necessary to always solve a problem directly by finding the one equation that you can plug the knowns into and crank out the unknown - the bottom line equation. It is often useful to use a two-step method where you solve for some intermediate variable that you don't know (and which may not even be requested). Then use this new known variable in yet another equation to find the unknown requested.