at the gradient of the graph decreases, meaning smaller increases in force are required to produce a larger increase in extension M1\n- States that plastic deformation occurs / the wire stretches much more easily in this region B1\n- Identifies that the wire reaches its breaking point $B$ at an extension of approximately $14.7\\text{ mm}$ to $15.0\\text{ mm}$ (corresponding to a force of $160\\text{ N}$) A1","marks":4,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"read_the_graph","label":"Read the force-extension graph","steps":[{"type":"text","order":0,"title":"Start at the limit","content":"Begin **after** the limit of proportionality, at an extension of $4.8\\text{ mm}$. In this region the plotted line is curved rather than straight, so force and extension are no longer directly proportional. This clear observation earns **B1**.","highlights":[{"text":"limit of proportionality (at an extension of $4.8\\text{ mm}$)","location":"specification"}]},{"type":"text","order":1,"title":"Interpret the curve","content":"As the curve moves towards $B$, it becomes less steep: its **gradient decreases**. Gradient here means the increase in force for each increase in extension. Therefore, progressively smaller increases in force produce a larger increase in extension. This explanation earns **M1**.","highlights":[{"text":"Describe the non-linear behaviour","location":"specification"}]},{"type":"text","order":2,"title":"Name the deformation","content":"The wire is now undergoing **plastic deformation**: it stretches much more easily and would not return fully to its original length if the force were removed. Stating plastic deformation, or that the wire stretches much more easily, earns **B1**."},{"type":"text","order":3,"title":"Read the breaking point","content":"Read point $B$ from both axes: the wire breaks at an extension of approximately $14.7\\text{ mm}$ (about $15.0\\text{ mm}$), when the force is $160\\text{ N}$. Giving this endpoint reading earns **A1**.","highlights":[{"text":"breaking point $B$","location":"specification"}]}]}],"generatedAt":"2026-07-22T09:36:22.936Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"f6613a87-c37f-4714-897c-670dd5fb3ec1","revisionId":"96562972-27bf-4965-bf68-e854b8550830","questionNumber":null,"questionType":"LA","specification":"A student investigates how a polymer resistance band stretches under load. They record the extension of the band as force is added (loading) and then as force is removed (unloading).\n\nTheir results are plotted on the force-extension graph below:\n\n![A graph of Force on the y-axis against Extension on the x-axis. There are two distinct curves forming a closed loop that starts and ends at the origin (0,0). The upper curve is labelled \"Loading\" and curves smoothly upwards. The lower curve is labelled \"Unloading\" and lies below the loading curve, forming a loop between them. Neither curve is a straight line. Labelled axes: Force (N) on the vertical axis, Extension (cm) on the horizontal axis. ](https://assets.mathsgenie.co.uk/aqa-qb/a771abc3-ff9b-4d62-abe3-4a686b498be3.png)","difficulty":5,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"9075dc91-11bc-4271-a5a9-cf0871bf1293","label":null,"content":"Explain how the curves on this graph show that the stretching behavior of the polymer resistance band is different from the stretching behavior of a typical metal spring.","markscheme":"- States that the graph for the polymer band is non-linear (does not obey Hooke's law), whereas a typical metal spring has a linear relationship (obeys Hooke's law) B1\n- States that the loading and unloading curves for the polymer band follow different paths (forming a hysteresis loop), whereas they follow the same path for a metal spring B1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"compare_curves","label":"Comp

Forces and springs

Question 25

Forces and springs Questions

Forces and springs

Question 25

Forces and springs Questions