Reflective Mental Overseer Questions:
- From what point of view will I choose to observe the action described in this problem ?

- Where will I place the origin and when will I start the clock running ?

Actions:
- Designate the location of the frame of reference in some manner like placing a "+" at the origin of the coordinate system on your sketch. This determines the value of x_o.  Normally x_o = 0 if you place the origin at the initial location of an object. When two or more objects are present, the initial position of all the objects cannot be zero unless they are at the same point initially.

- Choose when you will start the clock. This determines the value of t_o.  Normally t_o= 0 if you start the clock at the start of some action.

- Choose which direction will be positive and which direction will be negative. Normally, directions to the right are taken to be positive as are directions upwards.

- For rotational problems choose either clockwise or counterclockwise as the positive rotational direction.

Comment:
- The structural form of the equations that you generate to solve a problem will be different for different locations of the origin.

- Some frames of reference produce easier equations to solve.

- Switching your frame of reference in the middle of a solution will almost always lead to disaster unless you are consciously aware that you are doing so.

- The generic equations in the book generally apply to a particular frame of reference which you will need to modify to fit your selected point of reference.

- A frame of reference could also be moving.