Mechanics is a fundamental branch of physics that deals with the motion of objects and the forces that cause this motion. In the context of the International Baccalaureate (IB) Physics syllabus, mechanics is a core topic that lays the groundwork for understanding more complex physical phenomena. This study note will cover the essential concepts, equations, and principles in mechanics, breaking them down into digestible sections.
Example:
If a person walks 3 km north and then 4 km east, the total distance traveled is 7 km. However, the displacement is 5 km northeast, calculated using the Pythagorean theorem.
Common Mistake:
Confusing speed with velocity. Remember, speed does not have a direction, while velocity does.
Example:
If a car's velocity changes from 20 m/s to 30 m/s in 5 seconds, the acceleration is: $$ \text{Acceleration} = \frac{30 , \text{m/s} - 20 , \text{m/s}}{5 , \text{s}} = 2 , \text{m/s}^2 $$
Example:
If an object is dropped from a height, its velocity after ( t ) seconds is: $$ v = gt $$ and the distance fallen is: $$ s = \frac{1}{2}gt^2 $$
Note:
Horizontal motion has constant velocity, while vertical motion has constant acceleration due to gravity.
Example:
If a car of mass 1000 kg accelerates at 2 m/s², the force required is: $$ F = ma = 1000 , \text{kg} \times 2 , \text{m/s}^2 = 2000 , \text{N} $$
Example:
If a machine does 500 J of work in 10 seconds, the power is: $$ P = \frac{500 , \text{J}}{10 , \text{s}} = 50 , \text{W} $$
Tip:
When solving problems in mechanics, always start by identifying the known and unknown quantities and choose the appropriate equations to relate them.
This document provides a comprehensive overview of the key concepts in mechanics as per the IB Physics syllabus. Understanding these fundamentals is crucial for tackling more advanced topics in physics.