Modelling in Mechanics Flashcards Preview

EDEXCEL AS Maths > Modelling in Mechanics > Flashcards

Flashcards in Modelling in Mechanics Deck (26)
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1

What is the common model of a particle?

Dimensions of the object are negligible

2

What is the common model of a rod?

All dimensions but one are negligible, like a pole or a beam

3

What is the common model of a lamina?

Object with area but negligible thickness, like a sheet of paper

4

What is the common model of a uniform body?

Mass is distributed evenly

5

What is the common model of a light object?

Mass of the object is small compared to other masses, like a string or a pulley

6

What is the common model of an inextensible string?

A string that does not stretch under load

7

What is the common model of a wire?

Rigid thin length of metal

8

What is the common model of a smooth and light pulley?

All pulleys you consider will be smooth and light

9

What is the common model of a bead?

Particle with a hole in it for threading on a wire or string

10

What is the common model of a peg?

A support from which a body can be suspended or rested

11

What is the common model of air resistance?

Resistance experienced as an object moves through the air

12

What is the common model of gravity?

Force of attraction between all objects (acceleration due to gravity = g)

13

What are the modelling assumptions for particles?

• mass of the object is concentrated at a single point

• rotational forces and air resistance can be ignored

14

What are the modelling assumptions for a rod?

• mass is concentrated along a line

• no thickness

• rigid (does not bend or buckle)

15

What are the modelling assumptions for a lamina?

• mass is distributed across a flat surface

16

What are the modelling assumptions for a uniform body?

• mass of the object is concentrated at a single point at the geometrical centre of the body - the centre of mass

17

What are the modelling assumptions for a light object?

• treat object as having zero mass

• tension the same at both ends of a light string

18

What are the modelling assumptions for an inextensible string?

• acceleration is the same in objects connected by a taut inextensible string

19

What are the modelling assumptions for a smooth surface?

• assume there is no friction between the surface and any object on it

20

What are the modelling assumptions for a rough surface?

• objects in contact with the surface experience a frictional force if they are moving or are acted in by a force

21

What are the modelling assumptions for a wire?

• treated as one-dimensional

22

What are the modelling assumptions for a smooth and light pulley?

• pulley has no mass

• tension is the same on either side of the pulley

23

What are the modelling assumptions for a bead?

• moves freely along a wire of string

• tension is the same on either side of the bead

24

What are the modelling assumptions for a peg?

• dimensionless and fixed

• can be rough or smooth as specified in question

25

What are the modelling assumptions for air resistance?

• usually modelled as being negligible

26

What are the modelling assumptions for gravity?

• assume that all objects with mass are attracted towards the earth

• earth’s gravity is uniform and acts vertically downwards

• g is constant and is taken as 9.8ms-2 unless otherwise stated