Kinematics: Solving Motion problems for Velocity, Acceleration, Distance

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Kinematics Solving Motion problems for
Velocity, Acceleration, Distance
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Kinematics

• The problems well do involve either constant
  velocity or velocity which is changing in a
  uniform way. In other words, only problems with
  no acceleration or constant acceleration.
• I encourage you to always make a graph of the
  motion to help you visualize (and solve) the
  problem.
• When starting the problems, sometimes its not
  obvious which equation to use. If you are not
  sure, start somewhere and if that doesnt work,
  look at another relationship.

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Kinematics

• Velocity (ave) Total Distance/total time or
  Vave d/t
• Acceleration change in Vel / change in time, or
  A (V2 V1) / t
• When something is accelerating, then Vave
  (V1 V2) / 2

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Kinematics

• General Problem Solving Strategy
• Draw a graph of the problem, usually this is a
  velocity vs. time graph, including the details of
  what you know on the graph
• Write down all the known values and also what you
  are looking for.
• Solve using the Kinematic equations OR the graph
• On a Vel vs. Time graph, the area of the graph
  total distance traveled.

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Kinematics example

• A raven flies at 10 m/s for 7 sec. How far does
  it fly (this is simple, but illustrates a point
  about the graph)

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Another Kinematics Example with acceleration

• A Barracuda accelerates from rest at an accel of
  4 m/s/s for 6 sec. a) what is the final velocity?
  b) How far does it swim?

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Another example..

• You borrow your brothers Ferrari and are driving
  at 80 m/s when you see a cop and need to slow to
  20 m/s. This requires 4 seconds. a) What is your
  acceleration? And b) how far did you go?