A2L Item 258

Goal: Hone the concept of average velocity

Source: CTtil2;12;02

While traveling from Boston to Hartford, Person A drives at a constant
speed of 55 mph for the entire trip. Person B drives at 65 mph for half
the trip and then drives 45 mph for the second half of the trip. When
would B arrive in Hartford relative to A?

  1. B arrives before A.
  2. B arrives at the same time as A.
  3. B arrives after A.
  4. Not enough information.

Commentary:

Answer

(3) Many students are inclined to average the speeds and conclude that
they arrive at the same time. It is often useful to compare this
situation to the one in which time is halved.