Mechancis Anf Stats Cap Flashcards
Particle
Dimensions of the object are negligible
Mass of object concentrated at a single point
Rotational forces and air resistance can be ignored
Rod
All dimensions but one are negligible
Mass is concentrated along a line
No thickness
Rigid so doesn’t bend or buckle
Lamina
Object with area but negligible thickness, like sheet of paper
Mass is distributed across a flat surface
Uniform body
Mass is distributed evenly
Mass of the object is concentrated at a single point at the centre of the body
Light object
Mass of object is small compared to other objects
Treat object as zero mass
Tension the same at both ends of a light string
Smooth surface
Assume there is no friction between the surface and any object on it
Rough surface
Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force
Wire
Rigid thin length of metal
Treated as one dimensional
Smooth and light pulley
Pulley has no mass
Tension is the same either side of the pulley
Peg
A support from which a body can be suspended or rested
Dimensionless and fixed
Air resistance
Usually modelled as being negligible
Gravity
Assume all objects are attracted towards the earth
Earths gravity is uniform and acts downwards vertically
G is constant and 9.8 unless stated otherwise
Binomial distribution
4
Fixed number of trials
Two possible outcomes- success and failure
Fixed probability of success
Trials are independent of each other
Normal distribution
Bell shaped
Symmetrical mean=median=mode
Approximately 68%of data lies within one SD, 95% within 2 SD, 99.7% within 3 SD
Approximating a binomial
N is large
P is close to 0.5 as normal distribution is symmetrical
