Mech 1 Flashcards
When is an object at equilibrium?
When a = 0
SUVAT equation with v, u, a, t
v = u + at
SUVAT equation with s, u, v, t
s = ((u+v)/2) x t
SUVAT equation with s, v, a, t
s = vt - ((a x t^2)/2)
SUVAT equation with v, u, a, s
v^2 = u^2 + 2 x a x s
SUVAT equation with s, u, t, a
s = ut + ((a x t^2)/2)
f =
ma
w =
mg
If two connected particles are moving in the same straight line what can you do?
Treat them as one particle
Newton’s third law
For every action there is an equal and opposite reaction
What is the assumption for the following model? Particle
Mass of the object is concentrated at a single point. Rotational forces and air resistance can be ignored.
What is the assumption for the following model? Rod
Mass is concentrated along a line. No thickness. Rigid.
What is the assumption for the following model? Lamina
Mass is distributed across a flat surface.
What is the assumption for the following model? Uniform body
Mass of the object is concentrated at a single point at the geometrical centre of the body - the centre of mass.
What is the assumption for the following model? Light object
Treat object as having 0 mass. Tension the same at both ends of a light string.
What is the assumption for the following model? Inextensible string
Acceleration is the same in objects connected by a taught inextensible string.
What is the assumption for the following model? Smooth surface
Assume that there is no friction between the surface and any object on it.
What is the assumption for the following model? Rough surface
Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force.
What is the assumption for the following model? Wire
Treated as one dimensional.
What is the assumption for the following model? Smooth and light pulley
Pulley has no mass. Tension is the same on either side of the pulley.
What is the assumption for the following model? Bead
Moves freely along a wire or string. Tension is the same on either side of the bead.
What is the assumption for the following model? Peg
Dimensionless and fixed. Can be rough or smooth as specified in the question.
What is the assumption for the following model? Air resistance
Usually modelled as being negligible.
What is the assumption for the following model? Gravity
Assume that all objects with mass are attracted towards the Earth. Earth’s gravity is uniform and acts vertically downwards. g is constant and is taken as 9.8ms^-2 unless otherwise stated in the question.
