Mechanics Flashcards
What is a vector?
A quantity which had both magnitude and direction
What is a scalar?
A scalar quantity had a magnitude only
State what is means by the following modelling assumption: Particle
And state what the term means
Dimensions of the object are negligible
1) Mass of the object is concentrated at a single point
2) Rotational forces and air resistance can be ignored
State what is means by the following modelling assumption: Rod
And state what the term means
All dimensions but one are negligible
1) Mass is concentrated along a line
2) No thickness
3) Rigid
State what is means by the following modelling assumption: Lamina
And state what the term means
Object with area but negligible thickness
1) Mass is distributed across a flat surface
State what is means by the following modelling assumption: Uniform body
And state what the term means
Mass is distributed evenly
1) Mass of the object is concentrated at a single point at the geometrical centre of the body (centre of mass)
State what is means by the following modelling assumption: Light object
And state what the term means
Mass of the object is small compared to other masses
1) Treat object as having 0 mass
2) Tension the same at both ends of a light string
State what is means by the following modelling assumption: Inextensible string
And state what the term means
A string that does not stretch under load
1) Acceleration is the dame in objects connected by a taut inextensible string
State what is means by the following modelling assumption: Smooth surface
1) Assume that there is no friction between the surface and any object on it
State what is means by the following modelling assumption: Rough surface
And state what the term means
If a surface is not smooth
1) Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force
State what is means by the following modelling assumption: Wire
And state what the term means
Rigid thin length of metal
1) Treated as one dimensional
State what is means by the following modelling assumption: Smooth and light pulley
1) Pulley has no mass
2) Tension is the same on either side of the pulley
State what is means by the following modelling assumption: Bead
And state what the term means
Particle with a hole in it for threading on a wire or string
1) Moves freely along wire/string
2) Tension is the same on either side of the bead
State what is means by the following modelling assumption: Peg
And state what the term means
A support from which a body can be suspended or rested
1) Dimensionless and fixed
2) Can be rough or smooth as specified
State what is means by the following modelling assumption: Air resistance
And state what the term means
Resistance experienced as an object moves through air
1) Usually modelled as being negligible