Flashcards in Chapter 17 - Oscillations Deck (26)

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1

## Angular frequency?

###
2 x pie x frequency

(2 x pie)/T

2

## How do all oscillations begin?

### With an object in equilibrium before a force is then applied to it (it then begins to displace)

3

## Why does a pendulum travel quickest at point of equilibrium, when oscillating?

### When displaced, it speeds up as it travels towards its equilibrium position and then increasingly slows down as it goes past it

4

## What is displacement?

### Distance from the equilibrium position (x)

5

## What is amplitude?

### Maximum displacement from the equilibrium position (A)

6

## What is period?

### Time take to complete one full oscillation

7

## What is the frequency definition?

### Number of complete oscillations per unit time

8

## What do we use to compare the difference in displacement of two objects oscillating, or the difference for the same object at different times?

### Phase difference

9

## What is the phase difference of two objects in anti phase and what does this mean?

### Pie radians - one object is at max pos displacement when the other is at max neg displacement

10

## Definition of angular frequency?

### Describes the motion of an oscillating object (closely related to angular velocity of an object in circular velocity)

11

## What is simple harmonic motion?

### Common kind of oscillating motion where its acceleration is defined as = -angular frequency*2 ( negative omega or W) x displacement

12

## What is the constant in the acceleration for SHM?

### W*2 (omega/angular frequency squared)

13

## What is acceleration of an object directly proportional to?

### Its displacement

14

## What does the negative sign mean in SHM - negative omega*2 x displacement?

### The acceleration of the object is proportional to the displacement, in the opposite direction it

15

## What would the gradient of an acceleration vs displacement graph give?

###
The negative angular frequency squared

a/x = -W*2

16

## Is the period of an oscillating object dependent on the amplitude?

### No, as amplitude of the swing increases so does the average speed of the swing , therefore period doesn't change (isochronous oscillator)

17

## What shape is displacement vs time graph for SHM?

### Sinusoidal shape, amplitudes K if no energy lost

18

## Using displacement time graphs, how can you tell the speed is greatest when at 0 displacement?

### The gradient equals velocity and the gradient is greatest when displacement = 0

19

## At maximum displacements on a displacement time graph what can you tell?

### The speed using the gradient - will be zero as motion has momentarily stopped

20

## How can you use a displacement time graph to make a speed time graph?

### Using the gradient of each time interval to plot the speed against time

21

## How do you get an acceleration time graph using a speed time graph?

### The gradient of the line at each time interval will give the acceleration at those times

22

## Two equations to define displacement?

###
x=AcosWt

x=AsinWt

23

## What do the letters stand for in x=A(sin or cos)Wt?

###
A = Amplitude

W = Omega

t = time

24

## How do you know whether to use cos or sin displacement equation?

### Use sin equation for when an object begins at equilibrium, cosine equation should be used when an object has been released from its max displacement

25

## Calculation of the velocity of a simple harmonic motion?

### v=±W(√A*2-x*2)

26