Chapter 1 - Models

Question 1

What is modelling:

Answer 1

Making the problem simpler by ignoring some variables

Question 2

What does it mean to model something as a particle:

Answer 2

Its dimensions are negligible so rotational effects and air resistance is ignored

Question 3

What does it mean to model something as a rod:

Answer 3

All dimensions but 1 are negligible so it’s rigid and the mass is concentrated

Question 4

What does it mean to model something as a lamina:

Answer 4

Like paper, it’s got area but not height, so the mass is distributed over the area

Question 5

What does it mean to model something as a uniform body:

Answer 5

Mass is evenly distributed, there’s a centre of gravity at the centre of the object

Question 6

What does it mean to model something as light:

Answer 6

Its mass is negligible, the tension is the same at both ends

Question 7

What does it mean to model something as inextensible:

Answer 7

It won’t stretch, so acceleration is the same across two objects attached by it

Question 8

What does it mean to model something as smooth:

Answer 8

Ignore friction

Question 9

What does it mean to model something as rough:

Answer 9

There’s friction

Question 10

What does it mean to model something as a wire:

Answer 10

1 dimensional

Question 11

What does it mean to model something as a bead:

Answer 11

Moves freely with no friction, tension is the same either side

Question 12

What does it mean to model something as a peg:

Answer 12

Dimensionless and fixed

Question 13

What is a vector:

Answer 13

Something with direction and magnitude

Question 14

What is a scalar:

Answer 14

Something with just magnitude