Oscillations Flashcards
Define restoring force.
Restoring force is the force that is always acting towards the midpoint/equilibrium.
Define displacement.
A vector quantity of distance from the midpoint/equilibrium position.
What is the defining feature of an object oscillating with SHM?
The restoring force is directly proportional to the object’s displacement from its equilibrium position and in the opposite direction to the displacement
Describe a graph of restoring force vs displacement.
Restoring force on the y axis and displacement on the x axis.
Straight negative line through the origin.
F α –x
Describe a graph of acceleration vs displacement.
Acceleration on the y axis and displacement on the x axis.
Straight negative line through the origin.
The gradient is –ω^2.
What causes the restoring force in:
Pendulum
Mass-spring system
Component of tension.
Stretched or compressed spring i.e. tension.
Why are circular motion and SHM linked?
Viewed side on, an object moving in a circle will look identical to an object moving with simple harmonic motion.
What is the displacement-time graph for a pendulum, when t = 0 is the maximum displacement.
A cosine wave.
What is the velocity-time graph for a pendulum, when t = 0 is the maximum displacement.
A negative sine wave.
What is the acceleration-time graph for a pendulum, when t = 0 is the maximum displacement.
A negative cosine wave.
What is a quick way for differentiation of different trig.
sin ===> cos
/\ . . . . . . . .|
| . . . . . . . .\/
-cos <== -sin
What is the equation for x (displacement in y axis) in a displacement-time graph.
x = A cos(ωt)
What is the equation for x (velocity in y axis) in a velocity-time graph.
v = -Aω sin(ωt)
What is the equation for x (acceleration in y axis) in a acceleration-time graph.
a = -Aω2 cos(ωt)
How could you calculate the velocity at any given point in a velocity-time graph?
v = -ω x
