to reduce the impact of random errors M1\n- Suggests randomising the onset delay before the hazard appears to prevent the driver from anticipating or predicting the timing M1\n- Suggests standardising environmental factors (e.g. keeping ambient room lighting, noise levels, and audio volume identical for all trials) M1\n- Suggests allowing a practice run for participants to familiarise themselves with the controls, eliminating the learning effect M1\n- Suggests using a larger, more diverse group of participants to reduce the effect of individual physiological differences M1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"improve_reaction_data","label":"Improve reaction-time data","steps":[{"type":"text","order":1,"title":"Repeat and average","content":"For each driver, repeat the test several times and calculate their mean reaction time. A mean is the total of the results divided by the number of results; it reduces the effect of random errors.\n\nThis earns M1. In your answer, state both the improvement and its effect clearly.","highlights":[{"text":"Give **two** ways that the researcher can improve the quality of the reaction time data collected, other than ignoring anomalous results.","location":"specification"}]},{"type":"text","order":2,"title":"Remove anticipation","content":"Randomise the delay before each visual hazard appears. This stops drivers predicting when it will happen, so the measured reaction time is more valid.\n\nThis earns the second M1: state the improvement and its effect clearly.","highlights":[{"text":"the time interval between a visual hazard appearing on the screen and the driver fully depressing the brake pedal","location":"specification"}]}]}],"generatedAt":"2026-07-22T11:51:06.902Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"823f960d-cc8e-4ed7-a5b7-59d01dc00ba5","revisionId":"ef747e5e-7dc2-46c9-84a6-381520ff5d8a","questionNumber":null,"questionType":"MC","specification":"An autonomous delivery rover of total mass $m$ is travelling at a constant speed $v$ along a horizontal track. Its collision-avoidance sensors have a latency (reaction time) of $\\tau$ seconds before they can trigger the brakes. Once triggered, the brakes apply a constant opposing braking force $F$ until the rover comes to a complete stop.\n\nWhich of the following modifications would increase the total stopping distance of the rover by the **greatest** factor?","difficulty":8,"difficultyBand":"medium","totalMarks":1,"sourceTitle":null,"calculatorUse":null,"parts":[],"options":[{"id":"0a80bac3-4a56-482a-8420-f5d60a4938e4","content":"Doubling the total mass $m$ of the rover","correct":false,"markscheme":"Incorrect. This only doubles the braking distance component while leaving the thinking distance unchanged.","order":0},{"id":"c15b2b55-3e62-4262-ad98-09034790906e","content":"Doubling the sensor latency time $\\tau$","correct":false,"markscheme":"Incorrect. This only doubles the thinking distance component while leaving the braking distance unchanged.","order":1},{"id":"e56cdf04-f396-4d78-97db-fa39dfb7b276","content":"Doubling the initial speed $v$ of the rover","correct":true,"markscheme":"Correct. This doubles the thinking distance and quadruples the braking distance, leading to the greatest overall increase in total stopping distance.","order":2},{"id":"489cfa20-2c31-41db-9632-3e64fb5cfe87","content":"Reducing the constant braking force $F$ by half","correct":false,"markscheme":"Incorrect. This only doubles the braking distance component while leaving the thinking distance unchanged.","order":3}],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_physics","summaries":[{"id":"000f174a-f880-46aa-be16-262a9aecc843","difficultyBand":"easy","calculatorUse":null},{"id":"02ff2f91-7c36-4b3f-9156-0249936418e1","difficultyBand":"easy","calculatorUse":null},{"id":"03821492-4bf8-4643-b804-bf6a2d3d42e6","diffi

Forces, stopping and braking

Question 6

Forces, stopping and braking Questions

Forces, stopping and braking

Question 6

Forces, stopping and braking Questions