Problem-solving strategies:
uniform acceleration in one dimension

There are three equations which are most useful in solving problems. Assuming that the accelerating object is moving in the +x direction, 

                 x = xo + vot + ½at2
                 v = vo + at
                v2 = vo2 + 2a(x - xo).

Every problem has the same six variables: 

                 xo  original position (choose zero)
                 x  ending position (a positive distance in meters)
                 vo  original velocity (positive, in m/s)
                 v  ending velocity (positive, in m/s)
                 a  acceleration (positive or negative, in m/s2)
                 t  elapsed time (in seconds)
  1. If a problem involves a reversal in direction (such as a car slowing down, stopping and reversing course), break the problem down into two parts and solve for the motion in one direction at a time.
  2. Always have the object moving in the positive axis direction; in this way, velocities will always be positive numbers. If the object is speeding up, the acceleration is positive. If the object is slowing down, the acceleration is negative.
  3. For vertical free-fall problems, the acceleration is always known: -9.8m/s2 for rising and +9.8m/s2 for falling.
  4. Read the problem description. Put the six variables into two categories: known and wanted. Make sure that all information has first been converted into SI units.
  5. Choose the equation from the list that will enable you to solve for one of the wanted variables from some of the known variables. Do not choose an equation which has two of the wanted variables in it.

Common pitfalls include: interchanging the starting and ending velocities, using a velocity value as a known acceleration value, not using the correct sign for acceleration when plugging into an equation.

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