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General Physics I:

Sunil Karna

Subsection 3.1.4 Rules to follow while solving motion problems:

  1. Linear Motion Problems: When motion problems become complex (say, more than one object involved, or a single object experiences complex motion) one must subdivide the problem into several sub-problems according to the following steps:
    1. Draw pictures of the situation at the critical times denoting when one sub-problem begins and another ends. Label the drawings appropriately, indicating the positions, velocities, accelerations, and times involved. Use subscripts to distinguish the variables in one sub-problem from another.
    2. Write the appropriate equations for each sub-problem.
    3. Write the equations that relate one sub-problem with the others.
    4. List the given quantities and solve the equations simultaneously for the unknowns.
    5. To use equations of motion along vertical motion, take \(g\) as negative and upward direction as positive.
    6. Be careful on taking reference point (origin of coordinate). Choose the reference point at the position where event initiates or the ground in general.
  2. Relative Velocity Problems: When relative velocities are involved, use the following steps:
    1. List the given quantities in a form of notation that allows you to recognize which object is moving in what reference frame.
    2. Draw a diagram showing the relationship between the vector velocities of the problem.
    3. Write the equations relating the horizontal and vertical components of these vectors.
    4. Solve the equations simultaneously for the unknowns of interest.
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