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