| Exam Board | AQA |
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| Module | Paper 2 (Paper 2) |
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| Year | 2020 |
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| Session | June |
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| Topic | SUVAT in 2D & Gravity |
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16 Two particles \(A\) and \(B\) are released from rest from different starting points above a horizontal surface.
\(A\) is released from a height of \(h\) metres.
\(B\) is released at a time \(t\) seconds after \(A\) from a height of \(k h\) metres, where \(0 < k < 1\) Both particles land on the surface 5 seconds after \(A\) was released.
Assuming any resistance forces may be ignored, prove that
$$t = 5 ( 1 - \sqrt { k } )$$
Fully justify your answer.