Mechanics 8.2 Modelling assumptions Flashcards
Model of a Particle
Particle - Dimensions of the object are negligible
Rod Model
Rod - All dimensions but one are negligible, like a pole or a beam
Lamina model
Lamina - Object with area but negligible thickness, like a sheet of paper
Uniform body model
Uniform body -mass is distributed evenly
Light object model
Light object - Mass of the object is small compared to other masses, like a string or pulley
Inextensible string model
Inextensible string - A string that does not stretch under load
Rough surface model
Rough surface - If a surface is not smooth, it is rough
Wire model
Wire - rigid thin length of metal
Smooth and light pulley model
Smooth and light pulley - all pulleys you consider will be smooth and light
Bead model
Bead - Particle with a hole in it for threading on a wire or string
Peg model
Peg - A support from which a body can be suspended or rested
Air resistance model
Resistance experienced as an object moves through the air
Gravity model
Gravity - Force of attraction between all objects. Acceleration due to gravity is denoted by g.
Modelling assumptions for a particle
-Mass of all the object is concentrated at a single point
-Rotational forces and air resistance can be ignored
Modelling assumptions for a rod
-Mass is concentrated along a line
-No thickness
-Rigid (doesn’t bend or buckle)
