Modelling assumptions

Question 1

Modelling assumptions

Answer 1

Air resistance
Lamina
Rod
Tension is the same at both ends of a light spring. Here, the mass is very small(regarded as zero).
The surface is smooth
Wire
The surface is rough
Particle
Uniform body
Gravity
Inextensible

Question 2

Air resistance

Answer 2

The friction an object experiences as it moves through space

Question 3

Lamina

Answer 3

An object with two dimensions(length and width), such as a sheet of metal. Its mass is evenly distributed across a flat surface.

Question 4

Rod

Answer 4

An object with one dimension(length), such as a pole or a beam. Its mass is distributed along a straight line. It is rigid(does not bend or buckle).

Question 5

Smooth surface

Answer 5

This assumes there’s no friction between this surface and an object.

Question 6

Wire

Answer 6

A rigid, thin length of metal, treated as one dimensional, either smooth or rough

Question 7

Rough surface

Answer 7

This takes into account friction on surfaces

Question 8

Particles

Answer 8

Where dimensions of the object are negligible/unimportant. Its mass is concentrated at a single point. Air resistance and rotational forces can be ignored.

Question 9

Uniform body

Answer 9

Its mass is evenly distributed. Its mass is concentrated at the geometrical centre of the body(centre of mass).

Question 10

Gravity

Answer 10

The force of attraction to the Earth, measured at 9.8m/s2. It is uniform and acts vertically downwards

Question 11

Inextensible

Answer 11

When an object does not stretch under a load. Acceleration is constant in objects connected by a taut inextensible string.