Science Assessment ~ Topics ~ Energy: Forms, Transformation, Transfer, and Conservation ~ Item NG104002 ~ Student Performance

Imagine a ball on a track where no energy is transferred between the ball and the track or between the ball and the air around the ball. The ball goes past Position 1, then down and up a dip on the track, and past Position 2. Position 1 and Position 2 are at the same height.

Will the ball be going faster, slower, or at the same speed at Position 2 compared to Position 1? Why? (Remember that no energy is transferred between the ball and the track or between the ball and the air around it.)

Faster, because new energy in the form of kinetic energy (kinetic energy) will be made when the ball goes down the long side of the dip
Slower, because kinetic energy (motion energy) will be used up when the ball goes up the steep side of the dip
The same speed, because the amount of kinetic energy (motion energy) that the ball has will remain the same the entire time it was moving along the track
The same speed, because the total amount of energy in the system (ball and track) does not change as the ball moves along the track

Distribution of responses
Answer Choice		Overall	Grades			Gender		Primary Language
		n = 2939	4–5 n = 0	6–8 n = 1560	9–12 n = 1379	Male n = 1354	Female n = 1501	English n = 2647	Other n = 203
A.	Faster, because new energy in the form of kinetic energy (kinetic energy) will be made when the ball goes down the long side of the dip	23%	N/A	25%	20%	21%	24%	23%	22%
B.	Slower, because kinetic energy (motion energy) will be used up when the ball goes up the steep side of the dip	49%	N/A	50%	47%	48%	49%	48%	49%
C.	The same speed, because the amount of kinetic energy (motion energy) that the ball has will remain the same the entire time it was moving along the track	16%	N/A	15%	16%	18%	14%	16%	18%
D.	The same speed, because the total amount of energy in the system (ball and track) does not change as the ball moves along the track	13%	N/A	9%	16%	13%	12%	13%	11%

Science Assessment

Item NG104002: Assuming no energy transfer between a ball and the track it is moving in, the speed of the ball will be the same before and after rolling down into and up out of a dip because the total amount of energy in the system does not change.