You can find this problem with supplemental pics on page 6 at http://www.physics.princeton.edu/~mcdonald/examples/ph101_2006/learning_guide_ph101_2006.pdf(adsbygoogle = window.adsbygoogle || []).push({});

Suppose that the maximum possible acceleration for passengers standing on a subway is 0.1 m/s^2 and that two subway stations are 0.7 km apart.

What is the minimum possible time taken between the two subways stations?

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The answer is 170 seconds. I keep getting 118 seconds :(

My calculations are as follows:

x = (0.5)(acceleration)(time^2) where x = 700 meters and acceleration is 0.1

thus, sqrt(2x/acceleration) = time = 118

Can anybody tell me what I am doing wrong?

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# I can't get the answer?

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