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## How to get A in physics?

Nischal Singh Dangol Asked:

How to get A in physics?

*Answer:*

Whatever the syllabus or course, an **A grade** means “Excellent work indicating a clear mastery of the subject material”

This requires evidently a **basic understanding** of the subject, thorough with the fundamentals and the ability to apply the principles to solve problems creatively. One should be able to make suitable connections between concepts logically to solve the problem in hand. (Remember, Physics is often referred to as a Problem Solving Discipline)

**A grade in Physics** comes naturally if you start loving the subject and take active interest in applying the **concepts of Physics** to solve problems (in subject as well as in day to day life situations)

Also important :

- Maintaining good rapport is also important in getting an A grade.
- Attend all lectures/classes and never bunk
- Do your assignments sincerely and submit in time

Wish you all the best.

**Got some more suggestions? **

*Use the commenting system to post your ideas.*

## Physical Quantity

**Prabesh **wants to know more on **Physical quantities:**

Physical Quantityis a quantity which can be measured. eg; length, mass, force, time etc

(The quantities which cannot be measured are abstract. Eg; Love, anger intelligence)

## Physics Problem Link

Try to solve this Problem

Kinematics Problem

## Wave travelling from one medium to another

**Iqbal Lucky** asked

“when a wave enters from air to water, its wavelength changes but

frequency remains unchanged. why”

**Answer**

**Velocity of a wave = frequency x time period**

*V* = ν λ

When a wave travels from one medium to another, its velocity changes and so also is its wavelength, but frequency; which is the number of vibrations produced per second is independent of the medium, remains constant.

However, their is a phenomenon called Doppler Effect where the **apparent **frequency (**observed frequency**) is different from actual frequency and is caused by the relative movement between the source and observer (listener)

Got a better answer?

Please post it as comment.

## Limitations of Dimensional Analysis

**Ashmeeta Bhattarai** asked:

“What are limitations of principle of homogeneity of dimensional analysis?”

**The dimensional analysis has the following limitations**

- It fails while using it to derive a relation among physical quantities, if there are more than 3 unknown variables on which a given physical quantity depends
- It does not tell whether a given Physical quantity is a scalar or a vector.
- It does not tell us the value of constants involved
- It does not always tell us the exact FORM of a relation
- It cannot be used for deriving logarithmic, trigonometric or exponential relations
- A dimensionally correct equation may not always be the correct relation. (Because there are more than one physical quantity having the same dimensions)

Know some more? Write them as comments to this post

## Rain and Man problems – How to solve?

**Shashank Asked:**

“How to solve

rain and man problemsfrom motion in one dimension?”

**Answer:**

The problem is solved using principles of **vector addition**.

There is a simple logic to remember

**A/C = A/B x B/C**

If we represent diagrammatically (in the form of vectors) the velocity of rain wrt ground, velocity of man wrt ground and velocity of rain wrt man, then we can write

Vr/m = V r/g + Vg/m = V r/g – Vm/g = V r/g + (- Vm/g)

Where (- Vm/g) is the negative vector of Vg/m

I will be adding illustrations soon.

## Principle of Homogenity of Dimensions

**Binay Sharma** asked:

“Explain the applications of the

Principle of homogenity of Dimensionsand its importance”

**Principle of homogenity of dimensions** states that “For an equation to be dimansionally correct, the dimensions of each term on LHS must be equal to the dimensions of each term on RHS.”

Applications

1. To determine the dimensions of an unknown quantity in an equation

2. To check the accuracy of an equation

3. To derive a formula connecting the given (or assumed) physical quantities

4. To convert a physical quantity from one system of unit to other