# Physics Formulas for Class 11 Chapter 9 Mechanical Properties of Solids

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Here we are providing important Physics Formulas for Class 11 Students. These formulas are useful for every student studying physics. Learning physics formulas is important for exams because they provide a compact and precise way of expressing the fundamental concepts and laws of physics. They allow you to quickly recall the relationships between physical quantities and use them to solve problems. Additionally, many exam questions in physics will require you to apply these formulas, so having a solid understanding of them is crucial for achieving a high score on the exam.

### Mechanical Properties of Solids

1)
\begin{aligned} \text { Stress } & =\frac{F}{A} \\ \end{aligned}
2) $$Volume\,stress=\frac{F}{\text { Total area }}=\Delta P$$
3) $$Shear\,stress =\frac{\text { Tangential force }}{A}=\frac{F_t}{A}$$
4) $$Longitudinal\,strain =\begin{gathered}\Delta l \\ L\end{gathered}$$
5) $$Volume\, strain=-\frac{\Delta V}{V}$$
6) $$Shear\,strain=\theta=\frac{\Delta x}{L}$$
7) $$E=\frac{\text { Stress }}{\text { Strain }}$$
8) $$Y=\frac{F L}{A \Delta L}$$
9) $$Breaking\,stress =P=\frac{\text { Breaking force }}{C / S \text { Area }}$$
10) $$K=\frac{\Delta P}{-\Delta V / V}$$
11) $$C=\frac{1}{K}$$
12) $$\rho_f=\rho_i[1+C \Delta P]$$
13) $$K_t=Pressure$$
14) $$K_\phi=v \times Pressure\$$
15) $$Shear\, modulus \eta=\frac{F_t}{A \theta}$$ or $$\frac{F_t L}{A \Delta x}$$
16) $$\beta=\frac{\alpha r}{L}=Angle\,of\, shear$$

17) Relation between Y, K and Î·:
$$\frac{9}{Y}={ }_\eta^3+\frac{1}{K}$$
18) $$\sigma=\frac{\Delta r / r}{\Delta L / L} \quad$$ Value $$0 \leq \sigma \leq 0.5$$
19) Relation between Y, K and Ïƒ:
\begin{aligned} & Y=3 K(1-2 \sigma) \\ & Y=2 \eta(1+\sigma) \end{aligned}
20) Work done = Change in potential energy
\begin{aligned} & W=U=\frac{1}{2} \times \text { Force } \times \text { Elongation } \\ & W=U=\frac{1}{2} \times \text { Stress } \times \text { Strain } \times \text { Volume } \\ & W=U=\frac{1}{2 Y} \times \text { Stress }^2 \times \text { Volume } \\ & W=U=\frac{1}{2} \times Y \times \text { Strain }^2 \times \text { Volume } \end{aligned}
21) Elongation due to self weight
$$\Delta L=\frac{M g \times L}{2 A Y}$$
22) Breaking stress due to self weight
$$P=\frac{M g}{A}$$

(1) What are the best ways to remember physics formulas?

Here are a few effective ways to remember physics formulas:

1. Practice using the formulas: Regularly working through problems that require you to apply the formulas will help solidify your understanding of them and make it easier to recall them when needed.
2. Associate with physical concepts: Try to understand the physical concepts behind each formula, as this will help you to remember the formula and its purpose.
3. Create flashcards: Write the formula on one side of the card and its explanation or example on the other. Reviewing the flashcards regularly can help you memorize the formulas.
4. Make mnemonics: Use memory aids, such as mnemonics, to help you remember the formulas.
5. Repeat, Repeat, Repeat: The more you repeat and use the formulas, the easier it will become to recall them.

Remember, the key to effectively remembering physics formulas is consistent practice and repetition.

(2) How many formulas are there in class 11 physics?

Answer: The number of physics formulas in physics is difficult to quantify as new formulas are being developed and old ones refined all the time. Additionally, the number of formulas used in a particular area of physics can vary greatly depending on the level of study and the specific topic being covered.

(3) Is remembering physics formulas difficult?

Whether or not remembering physics formulas is difficult depends on several factors, including an individual’s learning style, prior understanding of the related concepts, and the amount of time and effort put into memorization.

For some people, memorizing formulas can be a straightforward process. However, for others, it may require more effort and repetition. The best approach to remembering physics formulas is to understand the underlying concepts behind the formulas and practice applying them to problems. This way, recall of the formulas will become more natural over time.

Additionally, there are several techniques that can help make the process of remembering formulas easier, such as creating flashcards, using mnemonics, and regularly reviewing and practicing with the formulas.

In conclusion, while remembering physics formulas may be challenging for some people, with the right approach and techniques, it can become easier and more manageable.