Modelling Flashcards
1
Q
Particle assumption
A
- mass of the object is concentrated at a single point
- rotational forces and air resistance can be ignored
2
Q
Rod assumption
A
- mass is concentrated along a line
- no thickness
- rigid (does not bend or buckle)
3
Q
Lamina assumption
A
- mass is distributed across a flat surface
4
Q
Uniform Body assumption
A
- mass of the object is concentrated at a single point at the geometrical centre of the body - centre of mass
5
Q
Light Object assumption
A
- treat object as having zero mass
- tension the same at both ends of a light string
6
Q
Inextensible String assumption
A
- acceleration is the same in objects connected by a taut inextensible string
7
Q
Smooth Surface assumption
A
- there is no friction between the surface and any object on it
8
Q
Rough Surface assumption
A
- objects in contact with the surface experience a frictional force if they are moving or are acted on by a force
9
Q
Wire assumption
A
- treated as one dimensional
10
Q
Smooth and Light Pulley
A
- pulley as no mass
- tension is the same on either side of the pulley
11
Q
Bead assumption
A
- moves freely along a wire or string
- tension is the same on either side of the bead
12
Q
Peg assumption
A
- dimensions are fixed
- can be rough or smooth as specified in the question
13
Q
Air Resistance assumption
A
- usually modelled as being negligible
14
Q
Gravity assumption
A
- 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 9.8 ms-1, unless otherwise stated in the question