| Exam Board | OCR MEI |
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| Module | C3 (Core Mathematics 3) |
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| Year | 2011 |
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| Session | January |
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| Topic | Non-constant acceleration |
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3 The area of a circular stain is growing at a rate of \(1 \mathrm {~mm} ^ { 2 }\) per second. Find the rate of increase of its radius at an instant when its radius is 2 mm .