ular path around a hydrothermal vent at a constant speed.\n\n![A marine research drone orbiting a hydrothermal vent](https://assets.mathsgenie.co.uk/aqa-qb/0becab98-626c-4d61-9f9e-0350c4ad5a6c.png)","difficulty":3,"difficultyBand":"medium","totalMarks":7,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"4c8410c8-d0f5-4fcc-a436-2abe9ac78879","label":"a","content":"Explain why the drone's velocity is not constant.","markscheme":"- Identifies that velocity is a vector quantity (or has both magnitude and direction) B1\n- Explains that as the drone travels in a circular path, its direction of motion is continuously changing B1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"velocity_direction","label":"Use velocity's direction","steps":[{"type":"text","order":0,"title":"Separate speed and velocity","content":"The drone has **constant speed**, meaning the size of its speed does not change. But **velocity** is a vector: it includes both speed (magnitude) and direction. Stating this definition earns the first mark.","highlights":[{"text":"constant speed","location":"specification"}]},{"type":"text","order":1,"title":"Follow the circular path","content":"As the drone travels around the circular path, its direction of motion continuously changes. Since direction is part of velocity, the velocity is not constant.\n\nThis earns the second mark: link the continuously changing direction directly to the velocity not being constant.","highlights":[{"text":"travels in a horizontal circular path","location":"specification"},{"text":"at a constant speed","location":"specification"}]}]}],"generatedAt":"2026-07-22T09:34:39.006Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"c813c401-8ff5-4b35-b6c9-4438692ba83f","label":"b","content":"The work done by the drone's propulsion system after completing one full orbit of the vent is \$16200\\text{ J}\$. It takes the drone \$135\\text{ s}\$ to complete one orbit.\n\nCalculate the power of the drone's propulsion system.","markscheme":"- Uses $\\text{Power} = \\frac{\\text{Work done}}{\\text{time}}$ M1\n- Calculates the power as $\\frac{16200}{135} = 120\\text{ W}$ A1","marks":2,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"power_calculation","label":"Calculate the power","steps":[{"type":"text","order":0,"title":"Choose the relationship","content":"Power is the rate at which work is done, so use\n\n$$P=\\frac{W}{t}$$\n\nwhere $P$ is power in watts, $W$ is work done in joules and $t$ is time in seconds. Writing this relationship earns **M1**.","highlights":[{"text":"The work done by the drone's propulsion system after completing one full orbit of the vent is \$16200\\text{ J}\$.","location":"specification"},{"text":"It takes the drone \$135\\text{ s}\$ to complete one orbit.","location":"specification"}]},{"type":"hyper_latex","block":{"nodes":[{"latex":"P=\\frac{16200\\ \\mathrm{J}}{135\\ \\mathrm{s}}"},{"latex":"P=120\\ \\mathrm{W}"}]},"order":1,"title":"Substitute and calculate","description":"Both quantities are already in the correct SI units: joules and seconds. Calculating 16200 divided by 135 gives 120 W. This earns A1."}]}],"generatedAt":"2026-07-22T12:14:57.443Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"f4f954d6-5b66-4b38-886c-1e3b0da33edd","label":"c","content":"After completing the orbit, the drone slows down from a velocity of \$12.4\\text{ m/s}\$ to a velocity of \$3.4\\text{ m/s}\$. The magnitude of the deceleration of the drone is \$0.6\\text{ m/s}^2\$.\n\nCalculate the time taken for the drone to change velocity.\n\nUse the equation: \\\\[\\text{acceleration} = \\frac{\\text{change in velocity}}{\\text{time}}\\\\]","markscheme":"- Determines the change in velocity: $\\Delta v = 12.4 - 3.4 = 9.0\\text{ m/s}$ M1\n- Rearranges the acceleration formula to make time the subject: $\\text{time} = \\frac{\\text{change in velocity}}{\\text{acceleration}}$ M1

Motion

Question 43

Motion Questions

Motion

Question 43

Motion Questions