Students often fail to see the kinematical constraint of a string connecting two accelerating objects. (discover)

Many students think that two blocks connected by a (continuously) taught inextensible string can move at different velocities and/or accelerations, even though the distance between the blocks remains the same.

Students who do well in quantitative problem solving have difficulties with purely conceptal problems. (discover)

Most students can determine the formulae needed, from the data given in many of the problems listed in introductory texts, without having an understanding of the physical situation involved.

 

Students fail to see acceleration as the ratio Dv/Dt. (discover)

Some student's view acceleration as the velocity that an object has during the time interval in question. Other students who realize that acceleration is brought about by a change in velocity, don't directly relate the corresponding time interval with that change. Still other students associate acceleration as the change in velocity over a distance traveled (Dv/Dx), rather than the time taken for the change.

Students use compensation arguments to incorrectly solve conceptual problems. (discover)

When given a problem involving two quantities, in which one quantity increases, while the second quantity decreases, students will often claim that the net result in the product (or other similar mathematical function) of the two quantities is unchanged, since the increase of one compensates for the decrease in the other.