Chapter 18 - Simple harmonic motion Flashcards
What kind of motion will a pendulum perform?
Simple harmonic motion
Give some other examples of simple harmonic motion
- child on swing
- object on spring moving up and down repeatedly
- ball-bearing rolling from side to side
What is equilibrium?
The centre point
What does an oscillating object do?
Moves repeatedly one way than in the opposite direction through its equilibrium position
What is the displacement of an object in SHM?
Direction and distance from equilibrium point
In one full cycle after being released from a non-equilibrium position, what does the displacement of an object do?
- Decreases as it returns to equilibrium, then
- reverses and increases as it moves away from equilibrium in the opposite direction, then
- decreases as it returns to equilibrium, then
- increases as it moves away from equilibrium towards it’s starting position.
Define the amplitude of an object in SHM
Maximum displacement of oscillating object from the equilibrium position
When are oscillations described as free vibrations?
If the amplitude is constant and no frictional forces are present/ no external forces.
System oscillates at it’s natural frequency
What is the time period (T) of an object in SHM?
time for one cycle of oscillation
Define frequency for an object in SHM?
number of cycles per second made by an oscillating object.
For 2 objects oscillating at the same frequency, what is the equation for their phase difference? (in radians)
phase difference = 2∏t/T
Draw the graph of displacement against time for an object in SHM
What does the gradient of the displacement-time graph show?
Velocity at the given time (velocity-time graph)
- v =d/t
Draw the graph of velocity against time for an object in SHM?
What does the gradient of the velocity-time graph show?
acceleration
Draw a graph of acceleration against time for an object in SHM?
Using the graphs, what is the relationship between acceleration and displacement?
acceleration is always in the opposite direction to the displacement
If the displacement-time graph is cos(x) what is the velocity-time and acceleration-time?
v-t - -sin(x)
a-t - -cos(x)
What is the definition of SHM?
oscillating motion in which the acceleration is:
- ) proportional to the displacement, and
- ) always in the opposite direction to the displacement (towards equilibrium position)
What is the equation definition of SHM?
a (directly proportional) -x
x = displacement
What is the definition of SHM including constant?
a = - (angular speed^2) x
What is the equation for displacement with respect to t?
x = A cos(angular speed x t)
A = amplitude