Oscillations | Edexcel A-Level Physics (9PH0)

Oscillations

100 questions
9 subtopics
Paper 2: Advanced Physics II
Paper 2 and Paper 3

Paper 2 content on simple harmonic motion: the condition that defines it, the displacement, velocity and acceleration equations and graphs, the mass-spring oscillator and the simple pendulum, energy in an oscillation, damping, and resonance..

It covers the conditions for simple harmonic motion, displacement, velocity and acceleration in simple harmonic motion, the mass-spring oscillator and the simple pendulum, displacement, velocity and acceleration graphs, reading period, amplitude and speed from oscillation graphs, energy in an undamped oscillation, damping and where the energy goes, free and forced oscillations and resonance and resonance in practice and determining an unknown mass.

Sample questions from Oscillations

Answer each one closed book first, then open the answer.

The conditions for simple harmonic motion

Why does a mass hanging on a spring perform simple harmonic motion when it is displaced vertically?

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An extra displacement x stretches the spring further, producing an extra force kx directed back towards equilibrium, which is exactly the condition F = −kx.
Displacement, velocity and acceleration in simple harmonic motion

State the equation for the velocity of a simple harmonic oscillator released from maximum displacement:

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v = −Aω sin ωt.
The mass-spring oscillator and the simple pendulum

State the equation for the period of a simple pendulum and the assumption it relies on:

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T = 2π√(l/g), valid provided the angular amplitude is small.
Displacement, velocity and acceleration graphs

Where is the displacement–time graph steepest, and what does this tell you?

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It is steepest where it crosses the time axis, at the equilibrium position, showing that the oscillator is moving at its maximum speed there.
Reading period, amplitude and speed from oscillation graphs

What does the area under a velocity–time graph for an oscillator represent?

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It represents the displacement of the oscillator over that time interval.
Energy in an undamped oscillation

For a swinging pendulum, what form does the potential energy take?

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It is gravitational potential energy, gained as the bob rises above its lowest point.
Damping and where the energy goes

What distinguishes light, critical and heavy damping?

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A lightly damped system oscillates with slowly decreasing amplitude, a critically damped system returns to equilibrium in the shortest time without oscillating, and a heavily damped system returns to equilibrium slowly without oscillating.
Free and forced oscillations and resonance

What is the key difference between a free and a forced oscillation?

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A free oscillation occurs at the system's natural frequency with no driver, while a forced oscillation takes place at whatever frequency the driver imposes.

The 9 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
The conditions for simple harmonic motion	Recall questions on the definition, the condition on the restoring force, what the minus sign means, the acceleration-displacement relationship, and an oscillation that is not simple harmonic.	10
Displacement, velocity and acceleration in simple harmonic motion	Recall questions on amplitude, period, frequency and angular frequency, the velocity and acceleration equations, and the phase relationships between the three quantities.	8
The mass-spring oscillator and the simple pendulum	Recall questions on both period equations and the assumption behind the pendulum's, why amplitude and bob mass do not matter, and determining g or a spring constant from oscillations.	14
Displacement, velocity and acceleration graphs	Recall questions on the shapes of the three graphs, what each gradient gives, where velocity and acceleration are zero, and the phase difference between them.	10
Reading period, amplitude and speed from oscillation graphs	Recall questions on obtaining period and amplitude accurately, estimating maximum speed from a gradient, what the area under a velocity-time graph gives, and how damping changes the trace.	10
Energy in an undamped oscillation	Recall questions on the energy changes through a cycle, where kinetic and potential energy peak, the form the potential energy takes, and how total energy depends on amplitude.	15
Damping and where the energy goes	Recall questions on what damping is, where the energy goes, light, critical and heavy damping, whether energy is conserved, and why plastic deformation damps so effectively.	10
Free and forced oscillations and resonance	Recall questions on free and forced oscillations, natural frequency, what resonance is, why energy transfer peaks there, and how damping changes the resonance curve.	10
Resonance in practice and determining an unknown mass	Recall questions on where resonance is useful and where it is a problem, reducing it in a structure, and the calibration graph that turns a resonant frequency into a mass.	13

Oscillations is 100 of the 1,616 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.