l,{"backHref":"/gcse/physics/aqa/questions","basePath":"/gcse/physics/aqa/forces-and-motion/questions","formulaUrl":null,"initialIndex":56,"initialQuestionWindow":[{"id":"aed6a105-c10f-42c9-83cd-bcbed384ab10","revisionId":"cf1422bf-f109-48f3-958a-54ef23abd64d","questionNumber":null,"questionType":"LA","specification":"","difficulty":3,"difficultyBand":"easy","totalMarks":5,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"9fd56566-ec8a-4cea-900c-6eba86f8a18e","label":"a","content":"Complete the sentences to explain why an object falling vertically at terminal velocity remains at a constant speed:\n\n\"An object falling vertically through a fluid at terminal velocity maintains a constant speed because the downward force, caused by ________, is balanced by the upward resistive force, caused by ________.\"","markscheme":"- gravity (or weight) B1\n- drag (or air resistance / fluid resistance) B1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"balanced_forces","label":"Identify the balanced forces","steps":[{"type":"text","order":0,"title":"Identify balanced forces","content":"At terminal velocity, the object **remains at a constant speed**. That means the resultant force is zero, so the upward and downward forces are balanced.","highlights":[{"text":"at terminal velocity remains at a constant speed","location":"specification"}]},{"type":"text","order":1,"title":"Complete the forces","content":"Fill the gaps with the names of the forces:\n\n> “An object falling vertically through a fluid at terminal velocity remains at a constant speed because the downward force, caused by **gravity**, is balanced by the upward resistive force, caused by **drag**.”\n\nWriting **gravity** (or *weight*) earns the first mark. Writing **drag** (or *air resistance* / *fluid resistance*) earns the second mark.","highlights":[{"text":"downward force, caused by ________","location":"specification"},{"text":"upward resistive force, caused by ________","location":"specification"}]}]}],"generatedAt":"2026-07-22T11:41:09.903Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"200d86a0-9c9d-4a9a-9d55-ae7a2ebd9efe","label":"b","content":"Write down the equation that links distance travelled (\$s\$), constant speed (\$v\$), and time taken (\$t\$).","markscheme":"- $s = vt$ (or any correct rearrangement such as $v = \\frac{s}{t}$ or $t = \\frac{s}{v}$) B1","marks":1,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"recall_relationship","label":"Recall the motion equation","steps":[{"type":"text","order":0,"title":"Recall the relationship","content":"For an object moving at **constant speed**, distance travelled is found by multiplying speed by time:\n\n$$s = vt$$\n\nThis is the required equation, so writing it correctly earns the **B1** mark.","highlights":[{"text":"links distance travelled (\$s\$), constant speed (\$v\$), and time taken (\$t\$).","location":"specification"}]}]}],"generatedAt":"2026-07-22T11:41:44.283Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"daeeeb16-63a5-4c7b-86ac-21828deb51b2","label":"c","content":"The distance between an earthquake epicentre and a seismic recording station is \$1.08 \\times 10^6\\text{ m}\$.\nA primary seismic wave (P-wave) travels through the Earth's crust at a constant speed of \$6.0 \\times 10^3\\text{ m/s}\$.\nCalculate the time taken for the P-wave to travel from the epicentre to the recording station.","markscheme":"- Attempts to use $t = \\frac{s}{v}$ with the given values: $t = \\frac{1.08 \\times 10^6}{6.0 \\times 10^3}$ M1\n- Calculates the correct time of $180\\text{ s}$ (or $3\\text{ minutes}$) A1","marks":2,"order":2,"markingRubric":null,"explanation":{"methods":[{"id":"distance_speed_time","label":"Use distance ÷ speed","steps":[{"type":"text","order":0,"title":"Choose the equation","content":"Time is found by dividing the distance travelled by the speed:\n\n$$t=\\frac{s}{v}$$\

Forces and motion

Question 14

Forces and motion Questions

Forces and motion

Question 14

Forces and motion Questions