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Item EG081004: Two objects that are moving at the same speed must have different masses in order to have different amounts of motion energy.

Two objects are moving at the same speed.  The objects have different amounts of kinetic energy (motion energy).  Which of the following must be true?

  1. The objects are different sizes.
  2. The objects have different shapes.
  3. The objects have different masses.
  4. The objects are made of different materials.
Distribution of responses
Answer Choice
Overall
Grades
Gender
Primary Language
 
n = 1769
4–5
n = 312
6–8
n = 841
9–12
n = 616
Male
n = 800
Female
n = 935
English
n = 1578
Other
n = 150
A. The objects are different sizes. 17%19% 19% 14% 21% 14% 17% 19%
B. The objects have different shapes. 11%11% 13% 10% 13% 10% 12% 9%
C. The objects have different masses. 55%48% 53% 62% 51% 59% 55% 56%
D. The objects are made of different materials. 16%23% 15% 14% 16% 17% 16% 16%