Oscillations - SHM Flashcards
Identify situations in which SHM will occur. Recognize gradient as velocity in a s-t graph. Total energy of an undamped SHM remains constant.
What does things around us ‘oscillate’ mean?
They undertake continuously repeated movements.
Give an example of motion that can be described as simple harmonic motion.
The motion of a swing.
What is the ‘restoring’ force?
The force trying to return the object to it’s center position.
This force is proportional to the distance from that center position.
F=-kx
Where k depends on the particular oscillating system.
What is amplitude?
The maximum displacement from the equilibrium position.
At this displacement, and at the equivalent displacement on the other side, the object will have zero velocity.
What are isochronous oscillations?
Oscillations in which the period is independent of the amplitude.
How do you find angular velocity=2(pi)f?
Equating equations for time period.
In the relationship between circular motion and SHM, what is the radius of the circle replaced by?
The amplitude of the oscillation.
What is the relationship between the s-t and acc’n-t curves?
They have the same form, but the acc’n acts in the opposite direction to the displacement.
When the displacement is zero, so is the acc’n. When x is at it’s maximum displacement, the acceleration is also at it’s maximum value.
How do you explain the equations for velocity and acc’n in SHM?
With x=Acos(w)t, derive velocity and acceleration using dx/dt and the second order differential of that.
Substitute x into second eq’n for a=-(w^2)x
How do you arrive at k=(w)^2m?
By equating a=-{(w)^2}x and a=-(kx)/m from ma=-kx
Draw the energy curves for SHM.
(see page 156)
