NGSS MS PS2.A Test: Motion and Stability: Forces and Interactions Covers topics from MS-PS2-1 and MS-PS2-2 Meant as an assessment-not a project, solution design, construction of arguments, etc. Includes multiple choice, matching, computations of average speed, acceleration, force, mass, etc. 4 page test, includes answer key. Complete the sentence with the correct choice of answer. 1. Motion is a change in _____________________ relative to a reference point. (speed or position) 2. Another name