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