AP Physics 1 Question 56: Answer and Explanation

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Question: 56

6. A bubble in a glass of water releases from rest at the bottom of the glass and rises at acceleration a to the surface in t seconds. How much farther does the bubble travel in its last second than in its first second?

  • A. at
  • B. (t - 1)a
  • C. (t + 1)a
  • D. at

Correct Answer: B


B The distance travelled in the first second can be found using the Big Five,

dfirst = v0tfirst +

Using tfirst = 1 s and v0 = 0 m/s since the bubble starts at rest, the equation becomes

The distance traveled in the last second can be found using another Big Five equation.

Using tlast = 1 s and vfinal = v0 + attotal = attotal, the equation becomes

dlast = attotala

The question is asking for the difference in the distance, so

dlastdfirst = attotalaa = attotala = (t – 1)a