17 - Oscillations Flashcards Preview

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Flashcards in 17 - Oscillations Deck (26)
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1
Q

What is displacement of an oscillation?

A

The distance from the equilibrium position

2
Q

What is amplitude of an oscillation?

A

Maximum displacement from the equilibriium

3
Q

What is the period of an oscillation?

A

The time taken to complete one full oscillation

4
Q

What is the frequency of an oscillation?

A

The number of oscillations per unit time

5
Q

What are the two key features of SHM?

A

Acceleration of the object is directly proportional to its displacement

Acceleration acts in the opposite direction to the displacement

a ∝ x
a = -kx

6
Q

What formula defines SHM?

A

a = -ω²x

a = acceleration
ω = angular velocity
x = displacement
7
Q

If you plot a graph of acceleration against displacement, what does the gradient represent?

A

-ω²

8
Q

When is acceleration minimum in SHM?

minimum = greatest negative

A

When displacement is maximum

9
Q

When is acceleration maximum in SHM?

A

When displacement is minimum

minimum = greatest negative

10
Q

What two equations can we use to calculate displacement based on a sine / cosine graph?

A

x = Asinωt (if displacement starts from amplitude)

x = Acosωt (if displacement starts from equilibrium)

11
Q

What is the equation for velocity in SHM?

A

V = ±ω√(A² - x²)

12
Q

What is the equation for velocity when displacement = 0?

A

Vₘₐₓ = ωA

Because velocity is maximum when displacement = 0

13
Q

At maximum amplitude, how is the energy stored?

A

All potential energy, either gravitational or elastic depending on the system

14
Q

At equilibrium, how is the energy stored?

A

All kinetic energy with no potential energy

15
Q

What is the equation for kinetic energy?

A

Eₖ = 1/2mv²

16
Q

What is the equation for elastic potential energy?

A

Eₚ = 1/2kx²

17
Q

How do you calculate the total energy at any point in SHM of a system?

A

Eₜ = Eₖ + Eₚ

18
Q

What does it mean when an oscillation is damped?

A

When an external force that acts on the object has the effect of reducing the amplitude of oscillations.

19
Q

What happens when an oscillation is damped?

A

The amplitude is reduced until the object comes to rest.

20
Q

What happens to the kinetic energy of the oscillations during damping?

A

It is transferred to another form, usually heat.

21
Q

What is a free oscillation?

A

When an object is displaced from its equilibrium and then allowed to oscillate without any external forces.

22
Q

What is natural frequency?

A

The frequency of the free oscillations of an object.

23
Q

What is a forced oscillation?

A

When an periodic driver force is applied to the object, causing it to oscillate at the frequency of the driving force, the driving frequency.

24
Q

What happens if the driving frequency is the same as the natural frequency?

A

The object will resonate, causing the amplitude to increase dramatically.

25
Q

What can happen if high amplitude oscillations due to resonance are not damped?

A

The system may break.

26
Q

How can resonance be useful?

A

Musical instruments to increase volume

MRI scans