IMPORTANT Physics Problem from Paper 3

Here is an important problem for A-Level Physics. This is a paper 3 problem from the OCR Specimen Physics Paper.
Please note that you can find the paper here:
https://www.ocr.org.uk/Images/171758-...
Also note that these are not official solutions and please visit the exam board's link above to access the official mark scheme.
Even though this is an OCR question the physics is applicable to all exam boards including AQA Physics, Edexcel Physics, Eduqas etc.
The question is on Newton's 2nd Law for a variable mass. Hope this is useful and it helps you learn.
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