In this set of questions, we examine physics educators' assessment of students' ideas related to forces.

Relevant NGSS standards are drawn from both MS-PS2 (Disciplinary Core Idea PS2.A) and HS-PS2 (Disciplinary Core Idea PS2.A). In particular, we focus on conceptual ideas; attending to the mathematical skills of students is outside the scope of this assessment.

Questions may attempt to address one idea, but frequently students bring in other ideas - so the delineation noted here does not necessarily hold when we look at student work.

Constant force means constant acceleration, not constant velocity:

Bucket lift (muddy - students think of this as an equal-and-opposite question)

Contact forces act only while objects are in contact, non-contact forces (gravity) are always acting:

Soccer kick

Ball toss (muddier - contact/noncontact, acceleration)

Bungee (muddier - contact/non-contact and spring force)

Kate's box (contact/noncontact and friction)

Force pairs are equal and opposite:

Pushing off