Topic C Key Terms Flashcards
What is SHM behaviour
The acceleration (or restoring force) is DIRECTLY PROPORTIONAL to the displacement from the rest point.
The acceleration is always towards the rest point.
what is the phase difference of one oscillation
One oscillation is from 0 radians to 2π radians.
What is the gradient of a T^2 on y axis, and mass on x axis graph
4pi^2/k
How does energy vary with time over one oscillation?
SHM systems constantly transfer energy between PE and KE.
Total Energy = KE + PE at all times.
Total Energy will be equal at all times (no energy loss).
How does energy vary with displacement x ?
SHM systems constantly transfer energy between PE and KE.
Total Energy = KE + PE at all displacements.
Total Energy will be equal at all displacements (no energy loss).
The energy graphs must not extend beyond the amplitudes.
If you start at the rest point, which formula should you use?
x = A . Sin (ω.t)
v = A.ω . Cos (ω.t)
a = - A.ω2 . Sin (ω.t)
so a = - ω2
A. Sin (ω.t)
(Hence a = - ω2 . x )
If you start at the amplitude which formula should you use?
x = A . Cos (ω.t)
v = - A.ω . Sin (ω.t)
a = - A.ω2 . Cos (ω.t)
(Hence a = - ω2 . x )
Where is max KE in a pendulum?
KEmax = Total Energy when x = 0 since the object is at max speed at the rest point and there is no PE since there is no restoring force at the rest point.
Mechanic waves
A wave that requires a physical medium through which to travel. Example - sound waves. Sound waves can not travel through a vacuum (empty space).
Electromagnetic Waves
Do not require a physical medium through which to travel. Electromagnetic waves can travel through a vacuum. Examples: Radio waves, visible light, x-rays, etc. All EM waves travel at the same speed (speed of light) in a vacuum.
Wave
A periodic disturbance that transfers energy through a medium.
Medium
The material through which a wave travels.
Transverse Wave
A wave in which the particles of the medium move perpendicular to the direction of energy transfer the wave motion.
Examples of transverse waves: EM Waves (light), water surface waves
Longitudinal Wave
A wave in which the particles of the medium move parallel to the direction of energy transfer.
Displacement (x)
Displacement, (distance with direction), that a given particle in the medium is from its rest point. Measured in metres.
Amplitude (A or Xo)
maximum displacement from the rest point. Measured in metres.
Time Period (T)
the time taken for one complete wave to pass a fixed point. Measured in seconds.
Frequency(f)
number of complete waves that passes a fixed point in one second. Measured in Hertz.
Wavelength (𝜆)
the distance from a peak to the next consecutive peak. Measured in metres.
Wave speed (v)
the distance that a given wave-front/peak progresses in one second. (m.s-1)
v = f . 𝝀
Intensity (Link to apparent brightness)
is the incident power of a wave per unit area. Units of intensity are (W.m-2)
I = P / area
what is Constructive Interference
Two or more waves meet at a point. If they are IN PHASE the resultant Amplitude increases. This is CONSTRUCTIVE INTERFERENCE.
what is Destructive interference
Two or more waves meet. They are OUT OF PHASE and this results in a decreased Amplitude we call this DESTRUCTIVE INTERFERENCE.
what is Principle of Superposition
The principle of superposition is that the resultant displacement at any point is the algebraic summation of the displacements of the individual waves at that point.
