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							                     Ohio Graduation Test for Science – March 2006
                                  Annotated Item 32


Standard and Benchmark Assessed:

Standard:        Physical Sciences
Benchmark:       E. Demonstrate that energy can be considered to be either kinetic (motion) or
                 potential (stored).


Multiple Choice Question:

32.   A student plans to collect data needed to calculate the kinetic energy of a thrown baseball.
      She plans to measure the distance from pitcher to catcher, the time it takes for the
      baseball to arrive in the catcher’s glove, the mass of the baseball, and the circumference
      of the baseball.

      Which of these measurements is not needed to calculate the kinetic energy?
      A.  measuring the mass of the ball
      B.  measuring the flight time of the ball
      C. measuring the circumference of the ball
      D. measuring the distance from pitcher to catcher


Commentary:

This multiple choice question asks students to determine which measurement is not necessary
for the calculation of the kinetic energy of a thrown baseball. Students must recall that kinetic
energy depends on the mass and velocity of the moving object, a baseball. Students may also
recall that kinetic energy is calculated by multiplying one-half by the product of the mass and the
squared velocity of the object (or KE = ½ mv2) but knowledge of this formula is not necessary to
successfully respond to this question. Students must understand that the velocity of an object is
dependent on the relationship between the distance the object travels and the elapsed time that
it travels. Students are provided a scenario involving a thrown baseball and are told that data
on a number of variables is to be collected. Students must utilize their knowledge of kinetic
energy within the context of this scenario to determine which of the proposed measurements is
unnecessary. Answer choice C is correct because the circumference of the baseball is not
necessary to perform the calculation and find the kinetic energy of the baseball. Answer choice
A is incorrect because kinetic energy depends on the mass of the baseball and is necessary to
perform the calculation. Answer choices B and D are incorrect since the flight time of the ball
and the distance that the ball travels are both necessary to determine the velocity of the ball
(v=d/t). The kinetic energy of the baseball depends on its velocity, so both the flight time and
the distance traveled are necessary information to perform the calculation.

The question is classified as Recalling / Identifying Accurate Science because this task requires
students to recall previously learned facts regarding how the kinetic energy of a moving object is
calculated. For this question, students do not need to recall the specific formula for the
calculation of kinetic energy but must know that the amount of kinetic energy depends on the
mass and velocity of the object.




Source: Ohio Department of Education                                                       July 05
                    Ohio Graduation Test for Science – March 2006
                                 Annotated Item 32


Performance Data:

The percent of public school students selecting answer choice C for question 32 on the March
2006 Ohio Graduation Test was 76%.


Keywords:      kinetic energy, mass, velocity




Source: Ohio Department of Education                                                   July 05