Oxford PAT 2009, Question 27

2009_page12 2009_page13

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7 thoughts on “Oxford PAT 2009, Question 27

  1. For part C, I assumed during that distance travelled he carried on starting and stopping, hence I used s=0.5t(U+V) where U is zero. Can you briefly explain why we assume constant velocity, thanks!

    1. He does carry on starting and stopping, but the question says he rapidly accelerates to velocity v. This basically means that he gets to v in negligible time and so he is travelling at v for the time during which he is moving.

  2. For part (f), why not include the energy needed for the car to travel 1km in addition to the energy transferred to the air (i.e. why not add your answer of 50kJ to 500kJ from part (d) ) ?

  3. Hello, I’m quite confused about question(c), should total energy include energy to restart the car ? In that case , answer will be doubled: mv^2d/s

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