A meter stick is released from rest, falls between someone's open fingers, and is caught after falling 30 cm. The reaction time is closest to (g = 10 m/s²)

0.245 s (t = \sqrt{2d/g}) d = \frac{1}{2}g t^2, so t = \sqrt{2(0.30)/10} = \sqrt{0.06} = 0.245 s.

Displacement, Velocity, and Acceleration

AP Physics 1· difficulty 4/5

g = 10

Explanation

d = \frac{1}{2}g t^2

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