Here are the main points that will be addressed in the videos. Please read these and think about them as you watch.

  • We notice an object’s speed by observing a change in position over an interval of time, but at single instant in time, speed cannot be observed.
  • We can approximate an instantaneous speed with an average speed over an interval of time immediately before or after the moment in time.
  • The average speed is typically either an over-estimate or an under-estimate of the instantaneous speed.
  • If we compute both an over-estimate and an under-estimate, we can compute how much error there might be in our approximation.