Driven oscillation is oscillatory motion kept going by an external periodic force. In Principles of Physics I, it shows how a system can vibrate at the driving frequency even while damping drains energy.
Driven oscillation in Principles of Physics I is motion that keeps going because something outside the system keeps pushing or pulling it at regular intervals. Instead of the object oscillating only because of its own inertia and restoring force, an external driver supplies energy every cycle.
That extra energy matters because real systems lose energy to damping. Friction, air resistance, internal friction in a spring, or electrical resistance all take energy out of the motion, so an unforced oscillator eventually slows down. A driven oscillator can keep a steady amplitude if the driver adds energy at the same rate the system loses it.
The frequency of the motion is set mainly by the driving force, not just by the object’s natural frequency. If you keep pushing a swing at a regular rate, the swing tends to respond at that push rate. The exact amplitude depends on how strong the driver is, how much damping is present, and how close the driving frequency is to the system’s natural frequency.
That last part is where resonance shows up. When the driving frequency is near the natural frequency, each push arrives at a time that adds energy efficiently, so the amplitude can grow very large. If the driving frequency is far from the natural frequency, the system still oscillates, but the energy transfer is less effective and the response is usually smaller.
Phase is part of the picture too. The displacement of the oscillator does not always line up with the driving force. Sometimes the force is pushing in step with the motion, and sometimes it is slightly ahead or behind. That phase relationship changes how much work the driver does on the system each cycle.
A good way to think about driven oscillation is as a balance: the driver feeds energy in, damping pulls energy out, and the resulting motion settles into a pattern determined by both. In a lab, you might see this with a mass on a spring being driven by a motor, or with an electrical circuit fed by alternating current.
Driven oscillation connects the energy ideas from simple harmonic motion to real systems that do not stay perfectly isolated. In the earlier SHM picture, energy swaps back and forth between kinetic and potential energy while the total stays constant. Driven motion adds a new part to that story: energy has to keep entering the system if the motion is going to persist.
That makes the term useful for reading graphs and explaining behavior. If a problem shows amplitude changing with driving frequency, you are usually being asked to connect that shape to resonance and damping. If the motion looks steady instead of dying out, the external force is supplying exactly enough energy to replace what is lost.
The concept also shows up in everyday and lab-style examples that physics classes like to use. A swing being pushed at the right rhythm, a mass-spring system driven by a vibrating support, or a circuit driven by alternating current all show the same basic idea: the system responds to a repeated outside input.
Once you can identify driven oscillation, you can explain why some systems stay small and controlled while others spike in amplitude. That is a useful problem-solving move in Principles of Physics I because the physics is not just about motion, it is about what sets the motion and where the energy comes from.
Keep studying Principles of Physics I Unit 14
Visual cheatsheet
view gallerynatural frequency
The natural frequency is the rate a system prefers to oscillate when nothing outside is driving it. Driven oscillation is compared against this frequency all the time, because the system responds very differently when the driving frequency matches or misses it. A lot of resonance questions are really asking you to compare the driver to the natural frequency.
damping
Damping is what removes energy from the oscillator through friction, resistance, or other losses. Driven oscillation exists partly because the external force has to overcome damping if the motion is going to continue. More damping usually means a smaller steady amplitude and a less dramatic resonance peak.
resonance
Resonance is the large response that can happen when the driving frequency is close to the natural frequency. In driven oscillation, resonance is the pattern you look for when amplitude grows much more than expected. It is not the same as just any oscillation, it is the especially efficient transfer of energy from the driver to the system.
energy transformation
Energy transformation describes how energy changes form during the motion. In a driven oscillator, energy is not only moving between kinetic and potential energy, it is also being added from outside and lost to damping. That means the total mechanical energy of the oscillator can rise, fall, or settle into a steady value depending on the balance of inputs and losses.
A problem set question on driven oscillation usually asks you to predict what happens to amplitude, phase, or energy transfer when the driving frequency changes. You may need to identify the resonance point from a graph, explain why the response grows near the natural frequency, or describe why damping keeps the amplitude from blowing up forever. If the class uses labs, you might also interpret a forced-vibration graph and say where the system is absorbing energy most efficiently.
When you see a swing, spring, or circuit example, first ask: what is doing the driving, what is losing energy, and what frequency is controlling the response? That lets you move from memorizing the term to actually analyzing the motion.
Natural frequency is the frequency a system has on its own, without a regular external driver. Driven oscillation is the motion produced when an outside force keeps pushing the system, so the observed frequency can follow the driver instead of the natural frequency. They are linked, but they are not the same thing.
Driven oscillation is oscillation maintained by a repeating external force, not just by the system’s own restoring force.
Damping removes energy from real oscillators, so a driver has to replace that energy if the motion is going to continue.
The driving frequency often controls the motion you observe, especially when the system settles into steady forced vibration.
Resonance happens when the driving frequency is close to the natural frequency, which can make the amplitude much larger.
Phase matters because the driver transfers energy most effectively when its timing lines up well with the motion.
It is oscillatory motion kept going by an external periodic force. The driver adds energy each cycle, which can balance the energy lost to damping and keep the amplitude steady.
In simple harmonic motion, the restoring force of the system itself produces the back-and-forth motion. In driven oscillation, an outside force is repeatedly adding energy and can set the observed frequency and amplitude.
Near resonance, the driving force arrives at a time that adds energy efficiently to the motion. That makes each cycle build on the last one more effectively, so the amplitude can increase a lot if damping is not too strong.
Damping takes energy out of the system, so it limits how large the oscillation can get. With stronger damping, the steady-state amplitude is smaller and the resonance peak is less sharp.