1. Kinematics

Important Misconceptions to Consider / Overcome

• Students don't readily differentiate between position, velocity, and acceleration.They have a single, undifferentiated idea of "motion."

• Position and velocity are sometimes confused. If car B overtakes and passes car A on the freeway, both traveling in the same direction, many students will say the cars have the same speed at the instant when B is alongside A. 

• Velocity and acceleration are frequently confused. When asked to draw velocity and acceleration vectors, students often draw acceleration vectors that mimic the velocity vectors. At a turning point (end of a pendulum's swing, top of the motion of a ball tossed straight up, etc.), nearly all students will insist that the acceleration is zero. This is an especially difficult belief to change.

• Acceleration is associated only with speeding up and slowing down. Very few students associate acceleration with curvilinear motion. This is not surprising, because a vector acceleration as we use it in physics is a definition, not a common sense observation. Many students, from high school physics, may know that circular motion has a centripetal acceleration. But this is a memorized fact; almost none can tell you why the acceleration points to the center.

• Students interpret a positive acceleration as always meaning "speeding up" and a negative accelerating as "slowing down," rather than associating the sign with the direction of the acceleration vector. This is a difficult idea to change, and for many students it becomes a serious difficulty when they get to Newton's second law.

• How can the motion of objects be predicted and/or explained? 

• Can equations be used to answer questions regardless of the questions’ specificity?

• How can the idea of frames of reference allow two people to tell the truth yet have conflicting reports?