“What is an inertial frame?”
“Are we in one?”
Estimated Time: 10 min, including wrap-up
This SWBQ requires familiarity with Newton's Second Law. Students should first be asked to write down some properties of inertial frames. After having a few minutes to respond, but without further discussion, students should be asked whether the classroom is an inertial frame.
Discuss student answers, emphasizing that the notion of inertial frame is context dependent: The classroom works fine for the Newtonian mechanics of small objects, with gravity viewed as an external force, but is noninertial due to rotational acceleration.