ts":[{"id":"19bec07a-75ba-42a4-957b-f82febc44969","label":"a","content":"Calculate the kinetic energy stored by the jet when it is travelling at \$64\\text{ m/s}\$.","markscheme":"- Recalls or uses kinetic energy formula $E_k = \\frac{1}{2}mv^2$ M1\n- Substitutes values to calculate $E_k = 0.5 \\times 12\\,500 \\times 64^2 = 25\\,600\\,000$ J (or $25.6$ MJ) A1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"kinetic_energy","label":"Calculate kinetic energy","steps":[{"type":"text","order":1,"title":"Choose the formula","content":"Kinetic energy is the energy an object has because it is moving. Use\n\n$$E_k=\\frac{1}{2}mv^2$$\n\nHere, $m$ is the mass in kg and $v$ is the speed in m/s. Writing this formula earns **M1**.","highlights":[{"text":"mass \$12\\,500\\text{ kg}\$","location":"specification"},{"text":"speed of \$64\\text{ m/s}\$","location":"specification"}]},{"type":"hyper_latex","block":{"nodes":[{"latex":"E_k=\\frac{1}{2}mv^2"},{"latex":"E_k=\\frac{1}{2}\\times 12\\,500\\times \\htmlData{anchor=speed-squared}{64^2}"},{"latex":"E_k=0.5\\times12\\,500\\times\\htmlData{anchor=squared-speed}{4096}"},{"latex":"E_k=\\htmlData{anchor=answer}{25\\,600\\,000\\text{ J}}=25.6\\text{ MJ}"}],"highlights":[{"color":"green","style":"box","anchor":"answer"}],"connections":[{"to":"squared-speed","from":"speed-squared","color":"orange","label":"square speed"}]},"order":2,"title":"Substitute and calculate","description":"Put the mass and speed into the formula, then square the speed before multiplying. This complete substitution and result earn the A1 mark."}]}],"generatedAt":"2026-07-22T12:15:09.364Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"b6e510fc-3202-45e7-b9db-833b98b6294b","label":"b","content":"Describe the energy transfer that takes place as the arresting cable brakes the jet and brings it to a complete stop.","markscheme":"- States that the kinetic energy of the jet decreases/is dissipated B1\n- Explains that this energy is transferred to thermal energy (heat) in the arresting cable system and the surroundings B1","marks":2,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"energy_transfer","label":"Track the energy transfer","steps":[{"type":"text","order":1,"title":"Identify the starting store","content":"The jet is moving before the cable catches it, so it has a **kinetic energy store**. As it is brought to a complete stop, this kinetic energy decreases (is dissipated).\n\nThis is the first marking point: state the decrease in the jet’s kinetic energy.","highlights":[{"text":"bringing it to a complete stop","location":"specification"}]},{"type":"text","order":2,"title":"State where it goes","content":"Braking causes heating in the arresting cable system, and energy also spreads to the surroundings. Therefore, the jet’s lost kinetic energy is **transferred to thermal energy in the arresting cable system and the surroundings**.\n\nThat destination of the energy earns the second marking point.","highlights":[{"text":"arresting hook catches a steel cable","location":"specification"}]}]}],"generatedAt":"2026-07-21T18:01:55.674Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"086c478e-b277-4f13-9586-220ab3dbb697","label":"c","content":"The jet is brought to a stop over a distance of \$95\\text{ m}\$. Calculate the average retarding force exerted by the arresting cable on the jet. Give your answer to 4 significant figures.","markscheme":"- Equates work done by the retarding force to the initial kinetic energy: $W = F \\times d = 25\\,600\\,000$ M1\n- Rearranges to solve for force: $F = \\frac{25\\,600\\,000}{95}$ M1\n- Obtains $269\\,500$ N (or $269.5$ kN / $2.695 \\times 10^5$ N) rounded to 4 significant figures A1","marks":3,"order":2,"markingRubric":null,"explanation":{"methods":[{"id":"work_energy","label":"Work done and kinetic energy","steps":[{"type":"text","order":1,"title

Work done

Question 17

Work done Questions

Work done

Question 17

Work done Questions