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

Students often display difficulty in graphing the motions of particles. They appear to lack the skill of dissociating the motion of the particle from the path that it is taking. Thus they redraw the path of the particle when asked to graph the particle's position or velocity versus time.

Students don't know what quantity in a graph will answer the question (coordinate, slope, or area). (discover)

Many students lack the knowledge of exactly what information the coordinate value, slope, or area under a graph provides. This causes them to look for obvious features on the graph to answer questions, regardless of the pertinence of those features.

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

Many students lack the ability to properly graph the position, velocity, and/or acceleration of an object whose motion is exhibited for them. Likewise, they lack the ability to demonstrate the motion represented by a position, velocity, and/or acceleration graph given to them.

 

Velocity must be positive, plotted above the time axis. (discover)

Many students have difficulty in associating a reverse in direction with a change in sign. Some students will insist that, like speed, velocity must be positive.

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

Many student's interpret a positive slope as speeding up (and a negative slope as slowing down) irrespective of the direction (sign) of the velocity.