Students have difficulty relating real world motions to a graph and vice-versa.

To probe this difficulty, construct a ball and track set-up in class (perhaps like the diagram below), and ask the students to plot the position and velocity of the ball versus time. Alternatively, you can give them a plot of a particle's postion or velocity versus time, and ask them to reproduce the motion on their desktops.

 Correct Answer

Depending on the set-up that you use, students with this difficulty will show a wide variety of incorrect responses. The links below point to some of the difficulties that you may see.

Related misconceptions/student difficulties that may arise in the question:

Students plot position and velocity graphs as the path of the particle.

Velocity must be positive, plotted above the time axis.

A positive slope for a negative velocity means the object is speeding up.