上海IGCSE暑期课程辅导，如何提高IGCSE物理成绩？

1

Which of the following is not a vector quantity?

A. Displacement

B. Force

C. Speed

D. Velocity

答案：C

在这道题目中，需要熟悉标量和矢量的概念。速度是标量，而其他选项都是矢量。容易犯错的地方是混淆速度和位移。

2

State Ohm's Law.

答案：Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.

在这道题目中，需要准确地表达欧姆定律。容易犯错的地方是使用不精确的术语或漏掉关键信息。

3

A car of mass 800 kg accelerates from rest to a speed of 25 m/s in 10 seconds. Calculate the work done on the car.

答案：

First, find the force:

F = ma

F = 800 kg × (25 m/s - 0 m/s) / 10 s

F = 800 kg × 2.5 m/s²

F = 2000 N

Then, find the work done:

W = F × d

Since d = v_avg × t, we have:

d = (0 m/s + 25 m/s) / 2 × 10 s = 125 m

So, W = 2000 N × 125 m = 250,000 J (Joules)

在这道题目中，需要熟悉力、加速度、功等概念和公式，以及如何进行多步计算。易错点包括单位或量纲错误以及计算过程中的错误。

4

Which of the following is not a vector quantity?

A. Displacement

B. Force

Explain how a greenhouse works in terms of heat transfer.

答案：

A greenhouse works by allowing visible sunlight to enter, which is absorbed by the surfaces inside the greenhouse, such as the plants and the ground. These surfaces then re-emit the absorbed energy as infrared radiation, which is a longer wavelength than visible light. The glass or plastic walls and roof of the greenhouse are more effective at trapping this infrared radiation, preventing it from escaping. This trapped radiation warms the air inside the greenhouse. In terms of heat transfer, the greenhouse primarily relies on the transmission of visible light, the absorption and re-emission of radiation, and the trapping of infrared radiation to maintain a warm environment.

在这道题目中，需要深入理解温室效应和热传递的原理，并准确地解释这些现象。易错点包括解释不清楚或不完整，以及使用错误或不精确的术语。