Applied - Mechanics - Modelling Assumptions

Question 1

What are the modelling assumptions of a particle?

Answer 1

Dimensions of the object are negligible, its mass is concentrated at a single point. Air resistance and rotational forces can be ignored

Question 2

What are the modelling assumptions of a Rod?

Answer 2

An object with 1 dimension (length). Its mass is distributed along a straight line, it has no thickness and is rigid (does not bend or buuckle)

Question 3

What are the modelling assumptions of a lamina?

Answer 3

An object with 2 dimensions (width and length). Its mass is evenly distributed across a flat surface

Question 4

What are the modelling assumptions of uniform body?

Answer 4

Its mass is evenly distributed. Mass of the object is concentrated at a single point at the geometrical centre of the body (the centre of mass)

Question 5

What are the modelling assumptions of a light object?

Answer 5

Its mass is very small and the mass is therefore treated as 0. Tension is the same at both ends of a light string

Question 6

What are the modelling assumptions of an inextensible string?

Answer 6

A string that does not stretch under load. Acceleration is constant in objects connected by a taut inextensible string

Question 7

What are the modelling assumptions of a smooth surface?

Answer 7

It is assumed that there is no friction between the surface and the object on it

Question 8

What are the modelling assumptions of a rough surface?

Answer 8

Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force

Question 9

What are the modelling assumptions of a wire?

Answer 9

A rigid thin length of metal which is treated as 1 dimensional

Question 10

What are the modelling assumptions of a bead?

Answer 10

particle with a hole in it for threading on a wire or string. It moves freely along the wire or string and tension is the same on either side of the bead

Question 11

What are the modelling assumptions of a peg?

Answer 11

A support from which a body can be suspended or rested. It is dimensionless and fixed

Question 12

What are the modelling assumptions of air resistance?

Answer 12

frictional resistance experienced as an object moves through the air

Question 13

What are the modelling assumptions of gravity?

Answer 13

The force of attraction to the earth, measured at 9.8 ms⁻². It is uniform and acts vertically downwards. all objects with mass are attracted towards the earth