Exam tip 1
Pay close attention to units in SHM calculations! Angular frequency should be in rad/s, time in seconds, displacement/amplitude in metres. A common error is mixing up degrees and radians for phase calculations.
9702 · 17.1
Simple harmonic oscillations — common mistakes
Common exam mistakes on 9702 Simple harmonic oscillations. Learn what loses marks, then practise the topic with Examiner’s Ink.
What makes an oscillation 'simple harmonic'?
An oscillation is simple harmonic if its acceleration is always directly proportional to its displacement from the equilibrium position and acts in the opposite direction. This specific relationship creates a smooth, sinusoidal motion.
How does energy change during Simple Harmonic Motion?
During SHM, energy continuously transforms between kinetic energy (due to motion) and potential energy (due to position). Kinetic energy is maximum at equilibrium, while potential energy is maximum at the amplitude points. For an ideal system, the total mechanical energy remains constant.
What is the difference between underdamping, critical damping, and overdamping?
These terms describe how quickly oscillations die out due to energy loss. Underdamping allows oscillations to decay gradually over many cycles. Critical damping brings the system back to equilibrium in the shortest time without any oscillation. Overdamping is when damping is too strong, causing a slower return to equilibrium than critical damping, also without oscillation.