Newtonian Dynamics Flashcards
dimensional analysis
write out variables with exponents of alpha, beta, gamma
plug in dimesions
make LHS and RHS compatible
kinematics
studies how the motion takes place and describes its geometrical features
dynamics
considers the origin of the motion and investigates the interactions between physical objects
x in polar coords
rsin theta cos phi
y in polar coords
rsin theta sin phi
z in polar coords
rcos theta
trajectory
set of points traced by the particle during its motion
xt diagram
time on x axis
position on y axis
uniform motion
zero acceleration
because of viscous effects, a particle moving in a fluid or a gas feels
an acceleration that is proportional to its velocity and opposite in direction
use dimensional analysis to work out k
2 dimensions
x=
rcos theta
2 dimensions
y=
rsin theta
curvilinear coordinate
s
identifies the location of the particle along the trajectory with respect to a certain origin
velocity of particle in vectorial form
v=ds/dt ut = vut
where ur is the unit vector tangent to the trajectory
relation between cartesian and polar unit vectors
ur=costheta ux + sintheta uy
utheta = -sintheta ux + costheta uy
equation for trajectory of particle is obtained by
eliminating the time variable from x(t) and y(t)
range
maximum distance xr travelled by the particle
The relation between the positions r, r’ of the particle, measured respectively by S, S′ is given by
vectorial equation
r=r0’+r’
poisson formula
db/dt=wxb
w is angular velocity vector whose magnitude is euqal to the angular velocity of the rotation
dux/dt=
wxux
(same for y and z)
relative motion: v=
v’+v0’+wxr’
centrifugal acceleration
ac=-wx(wxR) directed outwards
coriolis acceleration
as=-2wxv’ is orthogonal to both the angular velocity vector and the velocity v’ of the particle wrt S’
responsible for cyclones etc
first law - principle of inertia
consider a body on which no net forces act.
If the body is at rest it will remain at rest
If the body is moving with constant velocity it will continue to do so