Science Assessment ~ Topics ~ Force and Motion ~ Item FM067003 ~ Student Performance

An object is moving forward and no forces are acting on it. Every second, the object's speed is recorded. When the clock reads 0 seconds, the object's speed is 10 miles per hour (mi/hr). When the clock reads 2 seconds, a force begins to push the object forward. The force continues to act until the clock reads 4 seconds and then the force stops acting.

Clock →	0 seconds	1 second	2 seconds	3 seconds	4 seconds	5 seconds	6 seconds
Row A	10 mi/hr	9 mi/hr	8 mi/hr	8 mi/hr	8 mi/hr	7 mi/hr	6 mi/hr
Row B	10 mi/hr	10 mi/hr	10 mi/hr	11 mi/hr	12 mi/hr	13 mi/hr	14 mi/hr
Row C	10 mi/hr	10 mi/hr	10 mi/hr	11 mi/hr	12 mi/hr	12 mi/hr	12 mi/hr
Row D	10 mi/hr	11 mi/hr	12 mi/hr	13 mi/hr	14 mi/hr	15 mi/hr	16 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

Distribution of responses
Answer Choice		Overall	Grades		Gender		Primary Language
		n = 1796	6–8 n = 1129	9–12 n = 658	Male n = 837	Female n = 912	English n = 1582	Other n = 179
A.	Row A	20%	22%	17%	19%	21%	20%	19%
B.	Row B	17%	17%	17%	17%	17%	17%	19%
C.	Row C	39%	34%	46%	41%	36%	39%	35%
D.	Row D	25%	27%	20%	24%	26%	24%	27%

Science Assessment

Item FM067003: Use of tables of speed versus time, and information about forces acting on an object, to determine the object's speed at various times.