1st year Physics chp#1

 

Introduction to Physics:

Welcome to the exciting world of physics! It is the science that explores the fundamental principles that govern the universe. In this journey, we begin by understanding the basics of measurement and the language of quantities.

Physical Quantities:

Definition:

 Physical quantities are properties that can be measured and expressed with numbers.

 

 

International System of Units (SI):

Base Units:

These are the building blocks, like meter (length), kilogram (mass), second (time).

Supplementary Units:

 Radian and steradian, crucial for measuring angles and solid angles.

Derived Units:

 A whole spectrum derived from base and supplementary units, for example, speed (m/s), acceleration (m/s²).

Scientific Notation:

A simple way to express very large or very small numbers using powers of 10.

Notation and Errors:

Contention for Indicating Units:

 Clear rules for writing units with numbers to avoid confusion.

Errors and Uncertainties:

·         Random Error:

Unexpected fluctuations in measurements due to various factors.

·         Systematic Error:

 Constant deviation from the true value due to errors in the measurement system.

Significant Figures:

·         Definition:

•  Digits in a measurement that contribute to its precision.

·         Example:

•  In 25.4 mm, both digits are significant.

Precision and Accuracy:

Precision:

Imagine you are throwing darts at a dartboard. If your darts consistently land close to each other, even if they are not hitting the bullseye, you are achieving precision. Precision is about the consistency and reproducibility of measurements.

Example:

 You throw five darts, and they land close to each other but away from the bullseye. The closeness of the dart impacts indicates precision.

Accuracy:

Accuracy, on the other hand, is how close your average dart throw is to the bullseye, regardless of whether your throws are clustered together or scattered.

Example:

 Your average dart throw is right at the bullseye. Even if individual throws are spread out, the fact that, on average, you hit the target represents accuracy.

 

Assessment of Total Uncertainty:

1.      Addition and Subtraction:

·         Combine absolute uncertainties.

·         x₁ =10.50.1cm and x₂ =26.8cm is recorded as

·          x = x₂-x₁ = 16.3   0.2cm

2.      Multiplication and Division:

·         Combine relative uncertainties.

3.      Power Factor:

·         Apply the power to the relative uncertainty.        

4.      Uncertainty in the Average:

·         Calculate standard deviation.

5.      Timing Experiment:

·         Use appropriate equations for uncertainty.

 

 

Dimensions of Physical Quantities:

Every quantity has dimensions, such as length (L), mass (M), time (T). Understanding these dimensions helps us make meaningful equations and go deeper into the fabric of the universe.

So, get ready for an exciting journey through measurements, uncertainty, and the dimensions that govern our understanding of the material universe!