Y1, C8 - Modelling In Mechanics

Question 1

Modelling assumption of a particle

Answer 1

Mass is concentrated in a single point
Rotational forces and air resistance ignored

Question 2

Modelling assumption of a rod

Answer 2

Mass is concentrated along a line
No thickness
Rigid

Question 3

Modelling assumption of a lamina

Answer 3

Mass is distributed along a flat surface

Question 4

Modelling assumption of a uniform body

Answer 4

Mass is concentrated at a single point (the centre of mass)

Question 5

Modelling assumption of a light object

Answer 5

Treat object as having zero mass
Tension the same at both ends of a light string

Question 6

Modelling assumption of an inextensible string

Answer 6

Acceleration is the same in objects connected by the string

Question 7

Modelling assumption of a smooth surface

Answer 7

No friction

Question 8

Modelling assumption of a rough surface

Answer 8

Objects in contact experience a frictional force

Question 9

Modelling assumption of a wire

Answer 9

Treated as one dimensional

Question 10

Modelling assumption of a smooth and light pulley

Answer 10

Pulley has no mass
Tension is the same on each side of the string

Question 11

Modelling assumption of a bead

Answer 11

Moves freely along a wire or string
Tension is the same on either side of the bead

Question 12

Modelling assumption of a peg

Answer 12

Dimensionless and fixed
Can be rough or smooth (specified in question)

Question 13

Modelling assumption of air resistance

Answer 13

Usually modelled as being negligible

Question 14

Modelling assumption of gravity

Answer 14

All objects attracted towards Earth
Uniform and acts downwards
g is constant at 9.8ms^-2