peed to braking","description":"Braking distance is proportional to the square of the speed, so a modest reduction in speed has a large effect."},{"type":"text","order":3,"title":"Explain the speed reduction","content":"Reducing the shuttle's speed has two benefits:\n\n- it reduces the distance travelled during the system's reaction time;\n- it greatly reduces the braking distance because braking distance is proportional to $v^2$.\n\nTherefore the total stopping distance can remain within the fixed safety margin even though wet rails provide less friction. This completes the explanation for **A1**.","highlights":[{"text":"reduces the maximum operational speed","location":"specification"},{"text":"within a fixed safety margin","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:06:28.134Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"7063c53d-3c93-49f7-b7d9-751e94efd51e","revisionId":"9debcd6c-a23d-425d-ae1d-1e8fa9307338","questionNumber":null,"questionType":"LA","specification":"","difficulty":4,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"75b09c67-1d59-480c-b7d9-16f2e05da876","label":null,"content":"An experiment is conducted using a driving simulator to investigate how listening to a podcast (auditory distraction) affects a driver's reaction time. The simulator measures the time interval between a visual hazard appearing on the screen and the driver fully depressing the brake pedal.\n\nGive **two** ways that the researcher can improve the quality of the reaction time data collected, other than ignoring anomalous results.","markscheme":"- Suggests performing multiple repeat trials for each participant and calculating a mean reaction time 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}],"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",

Forces, stopping and braking

Question 5

Forces, stopping and braking Questions

Forces, stopping and braking

Question 5

Forces, stopping and braking Questions