Mechanics 1 Chapter 1

Mechanics 1 Chapter 1

1. Particle

   • An object that is small in comparison with other sizes can be modelled as a particle. This means the mass is considered to be at a single point. The fact it has no dimensions means we can ignore rotational effect as well as wind resistance.

2. Rod

   • This is when an object has a small dimesion in comparison with its other dimensions like a metre ruler can be modelled as a rod. This means the mass is distributed along a staight line.It has no thickness and does not bend.

3. Lamina

   • When an object's thickness is small in comparison to its length and width we model it as a lamina. This means it has its mass is distributed across the flat surface. It has no thickness and is two dimensional.

4. Uniform Body

   • If an object is uniform then its mass is distributed evenly across the object. This means we can consider the mass to be concentrated around one single point. This only works when an object has the even distribution of mass like a book. If you cut bits out of the book then it is no longer even so is modelled as a non-uniform body.

5. Light

   • When an object has a very low mass in comparison with others then we model it as having no mass at all.

6. Inextensible string

   • An inextensible string cannot be stretched in any way.

7. Smooth Surface

   • A surface that does not apply the force of friction due to it being smooth.

8. Rough Surface

   • A surface that does apply the force of friction due to its roughness

9. Wire

   • A rigid thin length of metal which is one dimensional is a wire. It can be either rough or smooth.

10. Smooth Light pulley

    • A pulley that is both smooth and light. (Check other definitions)

11. Bead

    • A particle which can be threaded onto and move freely along a wire.

12. Peg

    • A support from which an object can be suspended from or on which an object can rest. Dimensionless and normally fixed. Can be smooth or rough.

13. Air resistance

    • Objects moving through air will experience air resistance due to friction. We ignore this in M1

14. Wind

    • Unless mentioned ignore it

15. Gravity

    • The force of attraction to the Earth. This is called gravity. It is modeled as a constant and uniform as well as using the notation g. The acceleration due to gravity is assumed to be 9.8 unless otherwise stated on your exam paper.