# Topic 3 - Oscillations Flashcards Preview

## Edexcel Physics IAL unit 5 > Topic 3 - Oscillations > Flashcards

Flashcards in Topic 3 - Oscillations Deck (26)
1
Q

Oscillation

A

Continuously repeated movements

2
Q

Period (T)

A

The time taken for an object to complete one full oscillation

3
Q

Simple harmonic motion

A

The motion of an oscillating system.

There’s usually restoring force during the SHM, which tries to return the object to its Centre position

4
Q

Restoring force

A

F = -kx
Where the force is proportional to the distance from the center position and k is a constant that depends on the particular oscillating system

5
Q

Amplitude

A

The maximum displacement from the equilibrium position

6
Q

Period of a pendulum

A

T = 2π√l/g

Where L is the length of the pendulum string

7
Q

Angular velocity

A

• ω = θ/t
Where t is the time in seconds

• ω = 2πf

• ω = 2π/T
Where T is the period

8
Q

Horizontal distance

A

x = r cosθ

9
Q

Moving in a circle

A

x = r cos(ωt)

R can also be amplitude

10
Q

ω of a pendulum is √g/L

L is the length of the string of the pendulum

A

ω of a string is √k/m

K is the restoring force constant

11
Q

Acceleration acts in the opposite direction to the displacement

A

When displacement is zero so is the acceleration

And when X is max so is acc

12
Q

The displacement graph is a cosine graph

A

The acceleration graph is a negative cosine graph

The velocity is a negative sine graph

13
Q

During a swinging motion of a pendulum, at each end of the swing, it’s velocity is zero

A

So it has zero kinetic energy and a maximum potential energy at this point

14
Q

When the bob passes through the central position, it’s velocity is at a maximum

A

And the kinetic energy is at a maximum while the potential energy is at a minimum

15
Q

Free oscillation

A

A continuous exchange of PE and KE, caused by a restoring force which is proportional to the displacement.

16
Q

Natural frequency

A

The frequency at which the oscillating system naturally oscillates without external forces

17
Q

Forced oscillation

A

Forcing the the oscillating system to oscillate at another frequency than its natural one.
The frequency is called driving frequency

18
Q

Damped oscillations

A

These suffer a loss of energy in each oscillation reducing the amplitude over time

19
Q

Types of damping:

A

Under damping

Over damping

Critically damped (overshooting)

20
Q

Under damping

A

It’s when the oscillator completed several oscillations and the amplitude decreases exponentially
E.G. A normal pendulum

21
Q

Overdamping

A

The amplitude of the oscillation may drop so rapidly that the oscillator does not even complete one cycle
E.g. under water

22
Q

Critical damping or overshooting

A

When the oscillator returns to its equilibrium position in the quickest possible time without going past that position

23
Q

Undamped oscillation

A

Is when no energy is lost during oscillations

24
Q

Resonance

A

Is when a system is forced to vibrate at its natural frequency, absorbing more and more energy and thus increasing the amplitude.

25
Q

A simple setup of several pendulums can demonstrate resonance. They heavy swinging ball acts through the suspension wire to drive all the other pendulums at its natural frequency.

A

Only the pendulum with the same natural frequency will vibrate with a large amplitude. The pendulum has the same length of wire as the driving pendulum. The other pendulums show little movement because the driving frequency doesn’t match their natural frequency

26
Q

As the driving frequency applied to an oscillating system changes, it will pass through Natural frequencies of the system which causes large amplitude vibrations

A

The size of the vibrations at resonant frequencies can be so great that they damage the system