Sample Solutions

1.    I start my physics course with vectors and dimensions (units) and tell my students that if they are competent in these two areas of physics, then a quarter of their journey in studying physics has been mastered.

Make a serious effort to understand what's below and follow it up with some text you have at home. Feel free to contact me for further questions as and when they arise.

Now, this concept of vectors can be understood by answering a few questions. Suppose I asked you to stand up, walk up three steps ahead and then four steps to your right. Can you actually try this in your room? Mentally mark the point where you started and where you finished.

I guess it might have looked like this.

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The point where you started, let it be 0. The point where you finished let it be F. If I were to ask you how many steps you took or how many metres have you walked (assume each step is a metre long), they what would your answer be? ---------

Instead now if I ask you how far are you from where you started, can you apply Pythogoras' theorem and tell me the value? -----------

The answer to the first question is called distance. It is a scalar. There is no direction. Physical quantities such as distance are called scalars because they only have a magnitude (size) but no direction.

The answer to the second question is called displacement. It is a vector. There is a direction. Physical quantities such as displacement are called vectors because they have both magnitude and direction.

That should do for your first lesson on vectors. If you've gone ahead with this and send me your ANSWERS and have followed so far do get back to me. Before you start your second unit on vectors, you must also let me know if you have some idea of sine, cosine and tangent in a right angled triangle.