Modelling assumptions. 0.0 / 5 ? MathematicsMechanicsASEdexcel Created by: sydjow17Created on: 23-12-19 17:46 What are the assumptions when an object is modelled as a particle? (all dimensions negligible) Mass of the object is concentrated at a single point, and rotational forces and air resistance can be ignored. 1 of 14 What are the assumptions when an object is modelled as a rod? (all dimensions but one are negligible) Mass is concentrated along a line, no thickness and rigid (does not bend). 2 of 14 What are the assumptions when an object is modelled as a lamina? (object with area but thickness negligible) Mass is distributed across a flat surface. 3 of 14 What are the assumptions when an object is modelled as a uniform body? (mass distributed evenly) Mass is concentrated at a single point at the geometrical centre of the body - the centre of mass. 4 of 14 What are the assumptions when an object is modelled as a light object? (mass of the object is small compared to other masses, like a string or pulley) Treat object as having zero mass, and the tension is the same at both ends of a light string. 5 of 14 What are the assumptions of an inextensible string? (a string that does not stretch under load) Acceleration is the same in objects connected by a taut inextensible string. 6 of 14 What are the assumptions involved with smooth surfaces? There is no friction between the surface and any object on it. 7 of 14 What are the assumptions involved with rough surfaces? Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force. 8 of 14 What are the assumptions of modelling as a wire? (rigid thin length of metal) Treated as one-dimensional. 9 of 14 What are the assumptions when modelling a pulley as light and smooth? Pulley has no mass, and the tension is the same on either side of the pulley. 10 of 14 What are the assumptions when modelling an object as a bead? (particle with a hole in it for threading on a wire or string) It moves freely along a wire or string, and the tension is the same on either side of the bead. 11 of 14 What are the assumptions when modelling an object as a peg? (a support from which a body can be suspended or rested) It is dimensionless and fixed, and can be rough or smooth as specified in question. 12 of 14 What are the assumptions with air resistance in modelling? (resistance experienced as an object moves through the air) Usually modelled as negligible. 13 of 14 What are the assumptions with gravity in modelling? (force of attraction between all objects) That all objects with mass are attracted towards the Earth, and Earth's gravity is uniform and acts vertically downwards. 14 of 14
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