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Question 20 of 36

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SAT Subject Test

A teacher measures and records her own mass to an accuracy of better than 1 divided by 2 percent. Which of the following is most likely the mass that she recorded?

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6.43 invisible times text  kg end text

Correct Answer: 
No

60 invisible times text  kg end text

Correct Answer: 
No

64.3 invisible times text  kg end text

Correct Answer: 
Yes

600 invisible times text  kg end text

Correct Answer: 
No

643 invisible times text  kg end text

Correct Answer: 
No

The correct answer is 64.3 invisible times text kg end text. This question is intended to assess your knowledge of realistic values for physical quantities as well as an understanding of experimental error and significant figures. Only 60 invisible times text kg end text and 64.3 invisible times text kg end text are likely masses for an adult human. (If you need to compare the choices in pounds to see this, 1 invisible times text kg end text is approximately 2.2 pounds.) When recording measurements, it is assumed that there is some measurement error in the last digit recorded. For both possible values for the teacher's weight, 1 divided by 2 percent is about 0.3 invisible times text kg end text. Therefore, a mass recorded to better than this accuracy will indicate tenths of a kilogram.

Question Difficulty: 
medium