Science Assessment ~ Items ~ FM103001

An object is moving. Every second, the object’s speed is measured. When the clock reads 0 seconds, the object’s speed is 20 miles per hour (mi/hr). When the clock reads 2 seconds, a single constant force begins to act that slows the object down. This force continues to act during the time shown in the table.

Clock →	0 seconds	1 second	2 seconds	3 seconds	4 seconds	5 seconds	6 seconds
Row A	20 mi/hr	20 mi/hr	20 mi/hr	20 mi/hr	20 mi/hr	18 mi/hr	16 mi/hr
Row B	20 mi/hr	20 mi/hr	20 mi/hr	18 mi/hr	16 mi/hr	16 mi/hr	16 mi/hr
Row C	20 mi/hr	20 mi/hr	20 mi/hr	18 mi/hr	16 mi/hr	14 mi/hr	12 mi/hr
Row D	20 mi/hr	20 mi/hr	20 mi/hr	20 mi/hr	14 mi/hr	14 mi/hr	14 mi/hr

Which row of the table could be a correct representation of the object’s speed between 0 seconds and 6 seconds? Assume that if a change in speed has occurred, the change is shown in the table.

Row A
Row B
Row C
Row D

Details
Performance
NGSS

Topic: Force and Motion
Correct Answer: C
Misconceptions

Distribution of Responses

Chart showing distrubtion of responses for Item FM103001

Students Responding Correctly

Group	Correct	Total	Percent
Overall	1073	1796	60%
Grades
6–8	636	1127	56%
9–12	432	661	65%
Gender
Male	515	833	62%
Female	529	917	58%
Primary Language
English	961	1583	61%
Other	95	178	53%

View data table

Disciplinary Core Ideas: PS2.A The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.
PS2.A Newton's second law accurately predicts changes in the motion of macroscopic objects.

Science Assessment

Item FM103001: Use of tables of speed versus time, and information about forces acting on an object, to determine the object's speed at various times.