Simple Harmonic Motion

|SHM | Wave terms | Wave Phenomena |

associated with Comp 10.1 / chap 13

HW problems; answers: 1-4 and book

SHM Harmonic motion - presence of a restoring force

Simple Harmonic motion:

a linear restoring force, the force is directly proportional to the displacement and in the opposite direction


frequency/period/angular frequency
oscillation, cycle, vibration,
equilibrium (rest) position
Amplitude (linear/angular)
axis of symmetry
simple pendulum


-longitudinal (translational)
-torsional (rotational)
period (T) in sec - the time it takes for one complete oscillation, vibration, or cycle frequency (f) =1/T in Hz (s^-1) - the number of oscillations, vibrations, or cycles per second

angular frequency

one complete motion tothe point where the motion starts to repeat

amplitude (A) typically in m or °/rad - the maximum displacement of the object from its equilibrium position or its axis of symmetry

3 types of SHM:

1) longitudinal

2) transverse

3) torsional

Longitudinal: the mass is displaced parallel (or antiparallel) to the axis of symmetry or the amplitude is along the axis of symmetry creating areas of compression and rarefaction; amplitude is measured as a distance

transverse: the mass is displaced perpendicular to the axis of symmetry; amplitude is measured as a distance or an angle (angle is preferred) torsional: the mass is rotated around the axis of symmetry; amplitude is measured as an angle simple pendulum: system where the mass is concentrated a distance L from the pivot point

distance vs time
What is the period?

angle vs time
What is the period?

What is the actual equation (with units) for the curve?
The amplitude is mesured in ___.
The value "B" really represents ____.
Calculate the period of the motion.

damped oscillations
Amplitude decreases caused by an outside force.

resonance: when two oscillating systems share a common (or multiple of the same) frequency  

last modified 1-29-06