📚 Year 11 Eduqas Physics: Common Misconceptions and Corrections | Year 11 Eduqas 物理：常见误区与纠正方法
Many Year 11 students following the Eduqas Physics specification develop misunderstandings that can cost valuable marks in exams. These misconceptions often stem from everyday language or incomplete prior learning. This article identifies the most frequent errors and provides clear corrections, helping you to strengthen your understanding and boost your confidence.
很多学习 Eduqas 物理课程的 Year 11 学生会产生一些误解，这些误解可能会在考试中丢失宝贵的分数。这些误区往往源于日常用语或不完整的前期学习。本文列举了最常见的错误并提供清晰的纠正方法，帮助你加深理解、增强信心。
1. Confusing Mass and Weight | 混淆质量与重量
A common mistake is to treat mass and weight as the same quantity. In everyday language we say “an object weighs 5 kg”, but in physics weight is a force measured in newtons (N).
一个常见的错误是将质量和重量视为同一个量。在日常生活中我们会说“一个物体重 5 千克”，但在物理中重量是一种力，单位是牛顿（N）。
Mass is the amount of matter in an object and is measured in kilograms (kg). It does not change with location. Weight is the gravitational force acting on that mass and can be calculated using the relation between weight, mass and gravitational field strength.
质量是物体所含物质的多少，单位是千克（kg），它不随位置而改变。重量是作用在该质量上的重力，可以通过重量、质量和引力场强度之间的关系进行计算。
W = m × g
where g is the gravitational field strength (about 9.8 N/kg on Earth). To avoid confusion, always check the units: if a question asks for weight, give the answer in newtons. Remember that a 1 kg mass has a weight of roughly 9.8 N on Earth.
其中 g 是引力场强度（地球上约为 9.8 N/kg）。为避免混淆，务必检查单位：如果题目问的是重量，就用牛顿为单位作答。记住，地球上 1 千克的质量约重 9.8 牛顿。
2. Speed versus Velocity | 速率与速度的区别
Many students use speed and velocity interchangeably, but in physics velocity is a vector quantity – it has both magnitude and direction. Speed is a scalar; it only tells you how fast an object is moving.
许多学生将速率和速度混用，但在物理中速度是矢量，既有大小又有方向。速率是标量，只告诉你物体运动的快慢。
Velocity tells you how fast and in which direction. A car travelling at 30 m/s due north has a velocity of 30 m/s north; if the car turns a corner without changing speed, its velocity changes because the direction changes.
速度则告诉你快慢和方向。一辆车以 30 m/s 向北行驶，其速度为 30 m/s 向北；如果汽车转弯而速率不变，速度也会改变，因为方向改变了。
In exams, be careful with questions about circular motion or forces: an object moving in a circle at constant speed is constantly changing velocity, hence it is accelerating. The distinction is crucial for applying Newton’s laws correctly.
考试中，对待圆周运动或力的问题要小心：物体以恒定速率做圆周运动时，速度不断改变，因此它在加速。这一区别对于正确运用牛顿定律至关重要。
3. Acceleration Does Not Only Mean Speeding Up | 加速度不只是“加速”
Everyday language suggests acceleration is just getting faster, but in physics acceleration is the rate of change of velocity. This includes slowing down (often called deceleration) and changing direction.
日常语言中加速度似乎只是变快，但物理中加速度是速度的变化率。这包括减速（常称为负加速度）和方向改变。
An object is accelerating whenever its velocity changes – even if it is slowing down. If a car brakes from 20 m/s to 5 m/s, it has a negative acceleration, usually written with a minus sign.
只要速度改变，物体就在加速——即使它在减速。如果一辆车从 20 m/s 刹车到 5 m/s，它就具有负加速度，通常用负号表示。
a = (v − u) ÷ t
where v is final velocity, u is initial velocity and t is time taken. Always look at the direction of the change: if the calculated a is negative, the object is decelerating in the chosen positive direction.
其中 v 是末速度，u 是初速度，t 是所用时间。始终关注变化的方向：若计算出的 a 为负值，表明物体在所选的正方向上是减速的。
4. The Misconception that Motion Requires a Constant Force | 运动需要持续力的误区
One of the most stubborn misconceptions is the Aristotelian idea that a moving object must have a force pushing it. Newton’s First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by a resultant force.
最顽固的误区之一是亚里士多德式的观念：运动的物体必定受到力的推动。牛顿第一定律指出，除非受到合外力作用，物体将保持静止或匀速直线运动状态。
If you see a box sliding across a frictionless floor at constant velocity, the resultant force is zero – no forward push is required. In everyday life, friction usually acts to slow things down, which is why a constant force might be needed to maintain speed and balance friction.
如果你看到一个盒子在无摩擦的地板上匀速滑动，那么合外力为零——不需要向前的推力。在日常生活中，通常有摩擦力使物体减速，所以才需要持续的力来维持速度以抵消摩擦。
In exams, expect to state that if an object moves at a steady speed in a straight line, the forces on it are balanced. Do not assume that motion implies a net force.
考试中，应能说出：如果物体沿直线匀速运动，则作用在它上面的力是平衡的。不要假设运动就意味着有净力作用。
5. Action–Reaction Forces Act on Different Objects | 作用力与反作用力作用在不同物体上
Students often think the two forces in Newton’s Third Law cancel each other out because they are equal and opposite. However, these forces act on different bodies: one force acts on object A from object B, and the other acts on object B from object A.
学生常认为牛顿第三定律中的两个力因为大小相等、方向相反就会相互抵消。然而这两个力作用在不同的物体上：一个力是物体 B 对物体 A 的作用，另一个是物体 A 对物体 B 的作用。
A classic example is a book resting on a table. The book exerts a downward force on the table (its weight), and the table exerts an upward normal contact force on the book. These two forces are equal and opposite, but they are not an action–reaction pair! The correct Third Law pair to the book’s weight is the gravitational pull of the book upwards on the Earth.
经典例子是静止在桌上的书。书对桌子施加向下的力（它的重量），桌子对书施加向上的支持力。这两个力大小相等、方向相反，但它们并非作用力与反作用力对！与书的重量构成正确第三定律对的是书对地球向上的引力。
Remember: action–reaction pairs always involve two different objects and are of the same type (both gravitational, both contact, etc.). Identifying them correctly stops you from incorrectly cancelling forces in a free‑body diagram.
记住：作用力与反作用力总是涉及两个不同的物体，且属于同一类力（同为引力、同为接触力等）。正确识别它们可以避免在受力分析图中错误地将力抵消。
6. Do Heavier Objects Fall Faster? | 重物下落更快吗？
In the absence of air resistance, all objects fall with the same acceleration due to gravity (about 9.8 m/s² near the Earth’s surface). Galileo’s famous thought experiment and the Apollo 15 hammer–feather drop on the Moon both illustrate this principle.
在没有空气阻力的情况下，所有物体以相同的重力加速度下落（地球表面附近约为 9.8 m/s²）。伽利略著名的思想实验以及阿波罗 15 号在月球上的锤子与羽毛实验都证明了这一原理。
The confusion arises because on Earth, air resistance affects light, spread‑out objects more significantly. When the air resistance builds up to equal the weight, the object stops accelerating and reaches terminal velocity.
产生混淆是因为在地球上，空气阻力对轻而展开的物体影响更为显著。当空气阻力增大到等于重力时，物体停止加速并达到终端速度。
In Eduqas questions where you are told to ignore air resistance, clearly state that acceleration due to gravity is the same for all objects regardless of mass. You can use the equation of motion:
在 Eduqas 考题中如果要求忽略空气阻力，应明确说明重力加速度对所有物体都相同，与质量无关。你可以使用运动学方程：
v² − u² = 2 a s
m/s². This reminds you that mass does not affect the acceleration when only gravity acts.
并设 a = g = 9.8 m/s²。这提醒你，在只受重力作用时，质量不影响加速度。
7. Electric Current Is Not Consumed in a Circuit | 电流不会在电路中被消耗
A widespread misconception is that current is “used up” as it passes through components, so it becomes smaller after a lamp or a resistor. In a series circuit, the current is the same at every point.
一个普遍的误区是电流通过元件时会被“用完”，因此在灯泡或电阻之后电流会变小。在串联电路中，各点的电流都相等。
What is transferred is energy, not current. The battery provides energy, and components convert this energy into light, heat or motion, but the number of charges flowing per second (the current) remains constant around a single loop.
被转移的是能量，而不是电流。电池提供能量，元件将能量转化为光、热或运动，但在单一回路中每秒流过的电荷数（即电流）保持恒定。
Use the analogy of a closed water circuit: the same mass of water flows past every point each second. Similarly, charge is not lost – the same charge flows out of a bulb as flows into it.
可以类比闭合的水路：每秒流过各点的水量相同。同样，电荷不会消失——流入灯泡的电荷数与流出的一样多。
mber the golden rule for series circuits: I₁ = I₂ = I₃. If a question suggests a component “takes” is the same at all points, but the energy per charge (voltage) drops across the component.
记住串联电路的金科玉律：I₁ = I₂ = I₃。如果题目暗示一个元件“消耗”了一些电流，要纠正说电流在各点都相等，而每
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