Last modified on 18 March 2011, at 17:42

Physics Course/Oscillation/Oscillation Up and Down

The Oscillation up and down of a SpringEdit

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When apply a force on an object of mass attach to a spring . The spring will move a distance y above and below the equilibrium point and this movement keeps on repeating itself for a period of time . The movement up and down of spring for a period of time is called Oscillation

1Edit

The force acts on the object to pull the object down

F = m a

The Restoring Force of spring to push the object up can be calculated by Hook's Law

Fs = - k y

The oscillation stops when

Fs = - Fa
m a = - k y
y = \frac{m a}{k}
a = - \frac{k}{m} y
t = \frac{k}{m} \frac{y}{v}

2Edit

Any force acting on an object can be expressed in a differential equation

F = m \frac{d^2y}{dt^2}

Equilibrium is reached when

Fs = - Fa
F = m \frac{d^2y}{dt^2} = - k y
F = \frac{d^2y}{dt^2} + \frac{k}{m} y = 0
s^2 + \frac{k}{m} s = 0
s = ± j \sqrt{\frac{k}{m}} t
s = ± j \omega t
s = e^ j\omega t +  e^ -j\omega t
y = A Sin \omega t