xcel/questions","basePath":"/gcse/physics/edexcel/forces-stopping-and-braking/questions","formulaUrl":null,"initialIndex":12,"initialQuestionWindow":[{"id":"2df333d1-371d-4a21-9793-3e6d1ce6a408","revisionId":"93fe0b0e-0246-445a-9013-1337a1c2cd01","questionNumber":null,"questionType":"LA","specification":"","difficulty":4,"difficultyBand":"easy","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"2d5455dc-8fc6-4147-9c6b-8bc7171543a8","label":null,"content":"An engineering team tests the reaction time of an emergency safety-shutoff mechanism using a calibrated vertical drop-bar. In a series of trials, the mean distance the drop-bar fell before the brake fully engaged was $18.5\\text{ cm}$.\n\nCalculate the average reaction time of the shutoff mechanism.\nGive your answer to 2 significant figures.\n\nUse the equation:\n\n$$\\text{time}^2 = \\frac{\\text{distance}}{490}$$","markscheme":"- Substitutes the given distance into the equation to find $\\text{time}^2 = \\frac{18.5}{490} \\approx 0.0378$ (or equivalent) M1\n- Calculates the square root to find the time, giving $0.19\\text{ s}$ rounded to 2 significant figures A1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"substitute_then_square_root","label":"Substitute then square root","steps":[{"type":"hyper_latex","block":{"nodes":[{"latex":"\\text{time}^{2}=\\frac{18.5}{490}"},{"latex":"\\text{time}^{2}\\approx\\htmlData{anchor=time-squared}{0.0378}"}],"highlights":[{"color":"amber","style":"box","anchor":"time-squared"}]},"order":1,"title":"Calculate time squared","description":"Substitute the measured distance and divide by 490. This evaluated substitution earns M1."},{"type":"hyper_latex","block":{"nodes":[{"latex":"\\text{time}^{2}=\\htmlData{anchor=unrounded}{0.03775510204\\ldots}"},{"latex":"\\text{time}=\\sqrt{\\htmlData{anchor=under-root}{0.03775510204\\ldots}}"},{"latex":"\\text{time}=\\htmlData{anchor=time-value}{0.1943067216\\ldots\\text{ s}}"}],"highlights":[{"color":"amber","style":"box","anchor":"time-value"}],"connections":[{"to":"under-root","from":"unrounded","color":"green","label":"take square root"}]},"order":2,"title":"Take the square root","description":"Use the unrounded value here, then round the final time to 2 significant figures."},{"type":"text","order":3,"title":"Round the final answer","content":"To 2 significant figures, $0.1943067216\\ldots\\text{ s}$ becomes $\\boxed{0.19\\text{ s}}$.\n\nThis is the **A1** mark. Round only at the end, so the square-root calculation keeps enough accuracy.","highlights":[{"text":"Give your answer to 2 significant figures.","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:14:30.119Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"30bcb79a-70c0-4515-860f-abb501607914","revisionId":"227d35d5-c0a3-4631-81ae-e7165b2efbd9","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"093a87c4-b6f3-47ee-9bbb-51993648b5f8","label":null,"content":"A motorcycle is travelling along a straight road at a constant speed of $28\\text{ m/s}$.\n\nThe motorcycle travels a distance of $19\\text{ m}$ between the rider seeing a hazard on the road and applying the brakes.\n\nCalculate the rider's reaction time.\n\nGive your answer to 2 significant figures.","markscheme":"- Rearranges $\\text{distance} = \\text{speed} \\times \\text{time}$ to substitute values as $19 = 28 \\times t$ or $t = \\frac{19}{28}$ M1\n- Calculates the reaction time as $0.67857...\\text{ s}$ or $0.679\\text{ s}$ A1\n- Rounds to 2 significant figures to obtain $0.68\\text{ s}$ A1","marks":3,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"speed_time","label":"Use the speed equation","steps":[{"type":"text","order":1,"title":"Identify the reaction distance","content":"The $19\\text{ m}$ is the distance

Forces, stopping and braking

Question 11

Forces, stopping and braking Questions

Forces, stopping and braking

Question 11

Forces, stopping and braking Questions