PERIODIC MOTION
OSCILLATION OR VIBRATION
a motion that repeat itself with no net displacement
EQUILIBRIUM POSITION
the point that the object oscillates around.Also known as rest position.
DISPLACEMENT
How far the mass is from equilibrium point(x)
MAXIMUM DISPLACENT
how far the mass moves from the equilibrium point,(Xmax occurs at A..)
AMPLITUDE
The distance from the equilibrium point to the maximum displacement
PERIODIC MOTION
A vibration or oscillation repeat itself over and over the motion is said to be periodic
CYCLE
a complete to and from motion
PERIOD(T)
The time needed to complete one cycle.(units =seconds)
FREQUENCY(T)
The number of cycles completed in one second .(Hz)
f = 1/T
SIMPLE HARMONIC MOTION
any motion in which the restoring force is proportional to the displacement
RESTORING FORCE
the force that pushes or pulls the mass back to the equilibrium
HOOKE'S LAW
Fspring = Felastic =-kx
the applied force is opposite direction to the displacement
constant spring,k is N/m
the larger k value the stiffer the spring
Us = 1/2 kx^2
KE = 1/2mv^2
max potential energy = min kinetic energy,
max kinetic energy = min potential energy
GRAPH SHM
x(t) =A cos wt
the greater the dispacement , the larger the restoring force
energy is conserved
at max displacement :v = 0, a is largest,energy is all potential
at equilibrium,v is highest , a= 0,all is kinetic energy
SIMPLE PENDULUM
consists of a mass at the end of a lightweight cord.
The cord does not stretch, andthat its mass is negligible
if the angle is small,sin θ ≈ θ.
A physical pendulum is any real extended object that oscillates back and forth..
A torsional pendulum is one that twists rather than swings.
Damped harmonic motion is harmonic
motion with a frictional or drag force.
if the damping is small, we can treat it as an,―envelope‖ that modifies the undamped oscillation.
If b 2 > 4mk, ω’ becomes imaginary, and the system is overdamped
For b 2 = 4mk, the system is critically damped,
Forced vibrations occur when there is a periodic, driving force. This force may or may not have thesame period as the natural frequency of the system.
the amplitude of force vibration depends on the diferent between f and fo.
damping is due to friction and air