Year 9 Cambridge Engineering: Quick Guide to Memorising Key Terms | 剑桥九年级工程：关键术语速记指南

📚 Year 9 Cambridge Engineering: Quick Guide to Memorising Key Terms | 剑桥九年级工程：关键术语速记指南

Engineering at Year 9 introduces a vast new vocabulary that can feel like learning a foreign language. Terms such as ‘tensile strength’, ‘mechanical advantage’, or ‘closed-loop control’ are not just labels – they represent powerful concepts you will use to design and analyse the world around you. This guide breaks down the most important terms into logical groups and gives you memorable tricks, mnemonics and visual hooks to lock them into your long-term memory. Whether you are revising for an end-of-unit test or building a foundation for IGCSE, these memory aids will make you think like an engineer.

九年级工程课程引入了一套庞大的新词汇，有时就像在学习一门全新的语言。’抗拉强度’、’机械效益’或’闭环控制’等术语不仅是标签，更是你将来用来设计和分析周围世界的强大概念。本指南将最重要的术语分成逻辑清晰的组别，并为你提供难忘的技巧、助记口诀和视觉联想，帮助你牢固存入长期记忆。不论你是在准备单元测验，还是为IGCSE打基础，这些记忆方法都会让你像工程师一样思考。

1. Mastering Forces and Motion | 掌握力与运动

A force is simply a push or a pull, measured in newtons (N). The key equation linking force, mass and acceleration is F = m × a, known as Newton’s second law. To recall this instantly, use the mnemonic ‘Flying Monkeys Accelerate’ – the F stands for Force, M for Mass, and A for Acceleration. Remember that acceleration includes speeding up, slowing down and changing direction.

力就是推或拉，单位为牛顿（N）。将力、质量和加速度联系起来的关键方程是 F = m × a，即牛顿第二定律。要立即记住它，可以借用助记口诀 ‘飞翔的猴子加速’（Flying Monkeys Accelerate）—— F 代表力，M 代表质量，A 代表加速度。请记住，加速度包括加速、减速和改变方向。

F = m × a

Term	Quick Definition	Memory Hook
Velocity	Speed in a given direction (m/s)	Velocity has a Vector direction
Momentum (p)	Mass × velocity (kg·m/s)	‘Mr P’ flies across the room with momentum
Friction	Force resisting sliding motion	Friction Fights movement

Another useful trick is to think of momentum as ‘mass in motion’. The symbol p is used for momentum; imagine a big letter ‘P’ rolling down a hill – its motion is hard to stop. Friction always acts in the opposite direction to motion, so link it to ‘Friction Frustrates’.

另一个有用的技巧是把动量想象成’运动中的质量’。动量的符号是 p；想象一个大大的字母 ‘P’ 从山上滚下来——它很难停下来。摩擦力总是与运动方向相反，因此你可以把它和 ‘摩擦力阻挠运动’ 联系起来。

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2. Simple Machines and Mechanical Advantage | 简单机械与机械效益

Levers help us amplify force. A lever has a fulcrum (pivot), an effort (input force) and a load (output force). Mechanical Advantage (MA) tells us how many times the machine multiplies the effort: MA = Load / Effort. To remember the three classes of levers, picture the middle component: Class 1 has the Fulcrum in the middle (like a seesaw), Class 2 has the Load in the middle (like a wheelbarrow), Class 3 has the Effort in the middle (like a fishing rod). The mnemonic ‘FLE’ spells the middle part for each class: F, L, E.

杠杆能帮助我们放大力。一个杠杆包含支点（转轴）、动力（输入力）和负载（输出力）。机械效益（MA）告诉我们机械将动力放大了多少倍：MA = 负载 / 动力。为了记住三类杠杆，可以想象中间的那个部件：一类杠杆中间是支点（比如跷跷板），二类杠杆中间是负载（比如手推车），三类杠杆中间是动力（比如钓竿）。助记口诀 ‘FLE’ 正好对应各类杠杆的中间部件：F、L、E。

MA = Load / Effort

Lever Class	Middle Component	Example & Mnemonic
Class 1	Fulcrum	Seesaw – F is First
Class 2	Load	Wheelbarrow – Load in the Middle
Class 3	Effort	Fishing rod – Effort feels it

Another term is velocity ratio (VR), which compares the distance moved by the effort to the distance moved by the load. Think of VR as ‘Very Rapid effort’ when the effort moves a long way to lift the load a tiny distance.

另一个术语是速度比（VR），它比较动力移动的距离与负载移动的距离。当动力移动很长距离才能将负载抬起一小段距离时，可以把 VR 想成 ‘努力跑很远’。

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3. Energy, Work and Power | 能量、功与功率

Work is done when a force moves an object. Work is measured in joules (J) and the formula is W = F × d. Remember ‘Wife (W) does work with Force and distance’. Power is the rate of doing work, measured in watts (W). The equation P = W / t can be recalled by ‘Powerful Workers take less time’. Energy exists in many forms: kinetic (motion), gravitational potential (height), elastic (stretched springs).

当力移动物体时，就做了功。功以焦耳（J）为单位，公式为 W = F × d。可以记成 ‘老婆（W）用力和距离做功’。功率是做功的速率，单位为瓦特（W）。方程 P = W / t 可以用 ‘强大的工人花的时间更少’ 来记住。能量有多种形式：动能（运动）、重力势能（高度）、弹性势能（拉伸的弹簧）。

W = F × d

P = W / t

A mnemonic for gravitational potential energy GPE = m × g × h is ‘Mountain Goats Hop’. Here m stands for mass, g for gravitational field strength (10 N/kg on Earth), and h for height. Remember, the energy stored is like a ‘high mountain goat’ – the higher it is, the more potential it has.

重力势能 GPE = m × g × h 的助记是 ‘山羊跳’ (Mountain Goats Hop)。其中 m 代表质量，g 代表重力场强度（地球上为 10 N/kg），h 代表高度。记住，储存的能量就像’高处的山羊’——位置越高，势能越大。

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4. Electrical Quantities and Ohm’s Law | 电学量与欧姆定律

Voltage (V) is the ‘push’ that moves charges around a circuit. Current (I) is the flow of electric charge, measured in amperes (A). Resistance (R) is anything that slows the current down, measured in ohms (Ω). Ohm’s Law ties them together: V = I × R. To memorise, use the name ‘VIR’ – imagine a man called Vir who is an electrician. ‘Vir always follows the rule V equals I times R’.

电压（V）是推动电荷在电路中流动的’推力’。电流（I）是电荷的流动，以安培（A）为单位。电阻（R）是任何阻碍电流的事物，以欧姆（Ω）为单位。欧姆定律将它们联系在一起：V = I × R。记忆时可利用名字 ‘VIR’——想象一个名叫 Vir 的电工。’Vir 总是遵守 V 等于 I 乘 R 的规则’。

V = I × R

Quantity	Symbol	Unit	Visual Mnemonic
Voltage	V	Volt (V)	V pushes the I against R
Current	I	Ampere (A)	I is the flow of Invisible electrons
Resistance	R	Ohm (Ω)	Resistance Restricts flow

Another useful term is power in electrical circuits: P = V × I. Think ‘Powerful Vikings Invade’. Remember that resistors in series add simply (R_total = R1 + R2), while resistors in parallel combine with the reciprocal formula – a harder concept saved for IGCSE but worth noting.

另一个有用的术语是电功率：P = V × I。可以想成 ‘强大的维京人入侵’。记住，串联电阻简单相加（R_total = R1 + R2），而并联电阻要用倒数公式组合——这是 IGCSE 的难点，但值得提前了解。

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5. Material Properties and Selection | 材料性质与选择

Engineers choose materials based on properties such as tensile strength (resistance to pulling), compressive strength (resistance to squashing), hardness, ductility and malleability. A quick way to separate ductility and malleability: Ductile materials can be drawn into wires (both start with D: Ductile-Draw). Malleable materials can be hammered into thin sheets (Malleable-Mouldable like Play-Doh). Brittle materials break without much deformation – think of ‘Brittle Biscuits’.

工程师根据抗拉强度（抗拉伸）、抗压强度（抗挤压）、硬度、延展性和可锻性等性质来选择材料。快速区分延展性和可锻性的方法：延展性材料能被拉成金属丝（英语中 Ductile 和 Draw 都以 D 开头）。可锻性材料能被锤成薄片（Malleable 和 Mouldable 都类似捏橡皮泥）。脆性材料不发生明显变形就会断裂——联想 ‘脆饼干’。

Property	Definition	Mnemonic Link
Tensile strength	Max pulling stress before failure	Tensile = Tension = Tight rope
Hardness	Resistance to scratching or indentation	Hard Hulk resists scratching
Toughness	Ability to absorb energy before fracturing	Tough call – absorbs impact
Elasticity	Returns to original shape after load removed	Elastic band snaps back

A handy image for toughness vs hardness: glass is hard (scratches others) but not tough (shatters easily); rubber is tough (absorbs energy) but not hard. Think of ‘Hard Hats vs Tough Boots’.

一个区分韧性和硬度的形象图像：玻璃硬（能划伤其他物体）但不韧（容易碎）；橡胶韧（能吸收能量）但不硬。可以联想 ‘硬帽子与韧靴子’。

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6. Structural Members and Loads | 结构构件与载荷

Structures are built from beams, columns, struts and ties. A beam carries loads perpendicular to its length and bends. A column is a vertical member that carries compressive axial loads. The trick is to separate struts and ties: a strut is in compression (being squashed) – ‘Struts Squash’; a tie is in tension (being pulled) – ‘Ties are Tight’. In a simple triangular truss, the sloping members are often ties or struts depending on the load direction. A truss is a framework of triangles that spreads loads efficiently.

结构由梁、柱、压杆和拉杆构成。梁承受垂直于其长度的载荷并发生弯曲。柱是承受轴向压力载荷的竖向构件。难点在于区分压杆和拉杆：压杆承受压缩（被挤压）——’压杆受压’；拉杆承受拉伸（被拉紧）——’拉杆拉紧’。在一个简单的三角形桁架中，斜杆根据载荷方向可能是拉杆或压杆。桁架是一个由三角形组成的框架，能高效分散载荷。

Member	Type of Force	Memory Tip
Beam	Bending (tension + compression)	Beam Bends like a banana
Column	Compression	Column Crushed by Concorde
Strut	Compression	Strut gets Squashed
Tie	Tension	Tie is Tight like a guitar string

When you see a bridge truss, you can play ‘spot the strut and tie’: the top chord is often in compression (strut), the bottom chord in tension (tie). Visualise an archer’s bow – the string is a tie under tension, the bow itself is a strut under compression.

当你看到一个桥梁桁架时，可以玩’找出压杆和拉杆’的游戏：上弦杆通常受压（压杆），下弦杆受拉（拉杆）。想象一把弓——弓弦是受拉的拉杆，弓臂是受压的压杆。

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7. Systems: Input, Process, Output | 系统：输入、处理、输出

All engineered systems can be described using the universal Input-Process-Output (IPO) model. An input is a signal from a sensor (e.g., temperature, light). The process is carried out by a microcontroller or logic circuit. The output is an action performed by an actuator (e.g., motor, buzzer). The easy memory chain is ‘Sense → Think → Act’. Open-loop systems have no feedback; they just run blindly. Closed-loop systems use feedback to self-correct, like a thermostat. The key term ‘feedback’ loops back from output to input.

所有工程系统都可以用通用的’输入-处理-输出’（IPO）模型来描述。输入是来自传感器（例如温度、光）的信号。处理由微控制器或逻辑电路执行。输出是由执行器（例如马达、蜂鸣器）执行的动作。容易记住的链条是 ‘感知 → 思考 → 行动’。开环系统没有反馈，仅盲目运行。闭环系统利用反馈进行自我纠正，例如恒温器。关键术语’反馈’是从输出返回到输入的回路。

Input (Sensor) → Process (Microcontroller) → Output (Actuator)

A memorable mnemonic for a sensor-to-actuator sequence: ‘Light Dependent Resistor sees dark, Microcontroller decides, Motor spins’ – ‘LDR McD Motor’. Feedback is like a teacher marking your work and telling you how to improve; without it, you would keep making the same mistake.

传感器到执行器序列的一个好记口诀：’光敏电阻看到黑暗，微控制器做出决定，马达旋转’——缩写为 ‘LDR McD Motor’。反馈就像老师批改作业并告诉你如何改进；没有反馈，你会一直犯同样的错误。

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8. Manufacturing Processes | 制造工艺

Casting involves pouring molten material into a mould. Forging shapes metal by hammering or pressing, often improving its strength. Machining removes material (subtractive manufacturing). 3D printing adds material layer by layer (additive manufacturing). To remember casting, picture ‘casting a spell’ into a mould. For forging, think of a blacksmith forging a sword with heavy hammer blows – ‘Forging Fiercely’. Additive vs subtractive: ‘Add

Published by TutorHao | Year 9 工程 Revision Series | aleveler.com

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