SAT Subject Physics Practice Question 411: Answer and Explanation

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Question: 411

2. If a shaft were drilled through the center of the earth and all you had to do was step into the shaft to "fall" to the other side, and a 800N person took the trip, her weight at the exact time she passed through the exact center of the earth would be

A. zero.
B. 800N.
C. less than 800N but more than zero.
D. more than 800N.
E. Need more information.

Correct Answer: A

Explanation:

The correct answer is (A). Since , the person will be weightless at the center of the earth because r = 0, and all the mass of the earth is attracting the person from outside the center.

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