Oscillations — Class 11 CBSE Physics revision notes
A 6-page visual revision sheet for Oscillations, written for Class 11 CBSE Physics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Oscillations in one look
one condition makes it simple harmonic: the pull back home always scales with how far you've strayed
Periodic and oscillatory motion
- periodic motion repeats itself after a fixed interval, the period T
- oscillatory motion is periodic motion that goes back and forth about a mean position
- displacement x is measured from the mean position, and changes with time
- frequency counts repeats per second: ν = 1/T, and angular frequency ω = 2πν = 2π/T
Simple harmonic motion, the one condition
- in SHM the restoring force is proportional to the displacement from the mean position
- and it always points back toward the mean position: F = -kx
- that single condition is what makes a motion SHM, not just any back-and-forth swing
- it follows at once that a = -ω^2x, proportional to x and opposite in sign
Displacement and phase
- displacement
x(t) = Asin(ω t + φ) - phase, which fixes the state at time t
ω t + φ
Page 1 of 6. The full sheet, all 6 pages, opens free in the app.
What this Oscillations sheet covers
- Periodic and oscillatory motion
- Simple harmonic motion, the one condition
- Displacement and phase
- displacement
- phase, which fixes the state at time t
- SHM as a projection of circular motion
- Velocity and acceleration
- velocity
- acceleration
- Force law: a mass on a spring
- restoring force of the spring
- angular frequency
- period
- In the lab: a helical spring
- The two extremes of a swing
- At the centre, x = 0
- At an extreme, x = ±A
- Springs in combination
- in series
- in parallel
- Energy in SHM
- Energy formulas
- kinetic energy at displacement x
- potential energy at displacement x
- total, any instant
- Combining SHMs
- same line, same period: one SHM of amplitude
- in phase / opposite
- Simple pendulum
- Simple pendulum, the formulas
- In the lab: the simple pendulum
- Pendulum in a lift
- lift speeding up (or slowing while going down)
- lift speeding down (or slowing while going up)
- Physical pendulum
- a rigid body on a pivot, G a distance d below it
- moment of inertia about the pivot
- Torsion pendulum: angular SHM
- restoring torque of the twisted wire
- period, moment of inertia I
- Damped oscillations
- Damped oscillation, the equation
- displacement, damping constant b, mass m
- the amplitude envelope
- Forced oscillations and resonance
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Physics chapter by chapter against your real exam dates and free hours, and when the plan reaches Oscillations the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.