Year 1 - Mechanics Flashcards
8.2 What are the modelling assumptions for a particle?
Mass concentrated at a single point, Rotational forces/air resistance ignored
8.2 What are the modelling assumptions for a rod?
One dimension is negligible, mass concentrated along a line, rigid
8.2 What are the modelling assumptions for a lamina?
Thickness is negligible, mass is distributed across a flat surface
8.2 What are the modelling assumptions for a uniform body?
Mass concentrated at the object’s centre of mass
8.2 What are the modelling assumptions for a light object?
The object has zero mass
8.2 What are the modelling assumptions for an inextensible string?
String does not stretch under load, acceleration is the same in any connected objects
8.2 What are the modelling assumptions for a smooth surface?
The surface experiences no friction
8.2 What are the modelling assumptions for a rough surface?
The surface experiences friction between it and any object in contact with it
8.2 What are the modelling assumptions for a wire?
Rigid, thin line of metal, one dimensional
8.2 What are the modelling assumptions for a smooth and light pulley?
No friction, no mass, tension is the same in string on either side of the pulley
8.2 What are the modelling assumptions for a bead?
Particle with a hole that moves freely along a wire/string
8.2 What are the modelling assumptions for a peg?
A single point with no dimensions from which an object is suspended on, can be rough or smooth
8.2 What are the modelling assumptions for air resistance?
Usually modelled as negligible
8.2 What are the modelling assumptions for gravity?
Gravity is uniform and acts vertically downwards
9.4 Name the 5 suvat equations
v = u + at
s=((u + v)/2)t
v^2 = u^2 + 2as
s = ut + (1/2)at^2
s = vt - (1/2)at^2
10.1 What is Newton’s First Law?
An object in motion remains in motion unless acted upon by a resultant force
10.2 How do you find the resultant of two or more forces as a vector?
By adding the vectors
10.3 What is Newton’s 2nd Law?
F = ma
10.3 What is the equation that links weight, mass, and gravitational field strength?
W = mg
10.5 What can you say if all the particles in a system are moving in the same straight line?
They can be considered as one particle
10.5 What is Newton’s 3rd Law?
Every action has an equal and opposite reaction
10.6 What is a smooth pulley?
The tension in the string is the same on both sides of the pulley
11.1 What is represented by the gradient of a displacement-time graph?
Velocity
11.1 What is represented by the gradient of a velocity-time graph?
Acceleration
11.2 If displacement, s, is expressed as a function of t, what can the velocity be expressed as?
v = ds/dt
11.2 If displacement, s, is expressed as a function of t, what can the acceleration be expressed as?
a = d^2s/dt^2
11.3 How do you find the maximum displacement given an equation for displacement in terms of time?
Max. displacement is given by the turning point, to find it differentiate the equation and set ds/dt=0
